Canon Scanner – Unable to open TWAIN source

I have a Canon CanoScan 4400F Scanner and the other day I was unable to get it to work.  I use the Canon software CanoScan Toolbox to operate the scanner and when trying to scan I was getting the following error message:

image

---------------------------
CanoScan Toolbox
---------------------------
Unable to open TWAIN source
Please check connection
Then re-start Toolbox
---------------------------
OK  
---------------------------

Searching the Internet for this problem turned up several people having the same problem and several solutions which looked like they may or may not work.  One of the recommended solutions was to make sure a certain folder path is in your PATH environment variable.  As it turned out this was the problem, so here is how to add that path back into your environment variables.

First, determine the correct path to add into the PATH environment variable.  Look in C:\Windows\twain_32 and there should one other folder in there.  In my case it was  named CNQ4803.

image

This is the path that is needed to be added into the PATH environment variable.

C:\Windows\twain_32\CNQ4803

 

Now, follow these instructions to get to the dialog to modify the PATH environment variable.

Control Panel > System > and then choose Advanced System Settings in the left hand column.

image

This will bring up the System Properties dialog (it should already be on the Advanced tab).

image

At the bottom of this dialog is an Environment Variables button.  Clicking this button will bring up the Environment Variables dialog.

image

In the bottom panel, scroll until you find the variable named Path.  Select this one and then hit the Edit… button to bring up the Edit System Variable dialog.

image

In the Variable value text box, scroll all the way to the right and then add in the path C:\Windows\twain_32\CNQ4803 that was determined earlier.  Make sure to separate this value with a preceding semi-colon.  And also be careful not to make any other changes to this value.

Now OK your way out of all of the dialogs and CanoScan Toolbox will now work as expected.


 
Recommended Canon Scanners:

Canon CanoScan 9000F Color Image Scanner

Canon PIXMA MG5220 Wireless Inkjet Photo All-In-One (4502B017)



Published 02 November 2009 11:49 PM by Jeff Widmer
Filed under:

Comments

# Jon Davis said on 04 November, 2009 12:42 AM

Jeff: I want to thank you SO much for this information. I've had my 4400F about 2 years; today was the first time I had ever run into this 'twain' problem. For some reason, it has, many times in the past, 'lost' something in the CanoScan Toolbox. That only required uninstalling and reinstalling the Toolbox software. Anyway, I followed your instructions and all is fine now. Thanks again.

# Silvio said on 30 November, 2009 10:36 AM

jeff - many thanks for the info...you are a true gentleman

# Jackie said on 08 December, 2009 12:42 AM

Jeff - many thanks for your time and help.

Perfect solution.

# Denton said on 03 January, 2010 10:12 PM

Me Too!

My canon LiDE 70 has been working fine for years.  I recently installed Roxio Creator 2010 and I believe it is what munged my path. This fixed worked when reinstalling the drivers and CanoScan did not.  Many Thanks!

# Jarryd Semmens said on 17 January, 2010 07:58 AM

Fixed my scanner after reading this. Thankyou.

# Jay Vee said on 17 January, 2010 06:25 PM

Hi.  I tried this but it has made no difference. I downloaded a driver 64 bit for Vista 7 home version (32 bit version didnt download). I have canoscan lide 25.

Any further suggestions please?

# Sparky said on 26 January, 2010 09:33 PM

I've also started running Win 7 64-bit and this scanner simply will not work with it.  This fix did not help. I've been working on it for days and am just going to give it away to a friend and buy another scanner.  Anything but a Canon.

# tiger said on 08 February, 2010 10:38 PM

you are the man

# RW said on 09 February, 2010 03:25 PM

Jeff, this worked!  I spent the whole morning checking blogs and the Canon site.  Thanks so much for sharing ...

# Dhanunjay said on 22 March, 2010 02:14 PM

Thanks for your help it resolved my problem.

# Ronny said on 23 March, 2010 09:46 AM

Big thanks. I was about to do some reinstall and was saved by this post!

# Lone Wolf said on 31 March, 2010 10:19 AM

Mucho Gracias Senor Jeff!  apparently an Oracle XE  installations messed my path.

God Bless!

# thanks said on 02 April, 2010 04:05 AM

veeeeeeeeeery thanks

# Chuck said on 21 April, 2010 04:46 PM

Jeff!!  Thanks a bunch!!!!!

# Nicole Hamilton said on 10 May, 2010 01:47 AM

When Canon's miscreant CanoScan app suddenly stopped working with my 8400F scanner, I tried everything else I could think of but nothing worked.  Rebooting, system restoring, reinstalling the app, reinstalling just the driver, running in compatibility mode, yada, yada.  Nothing worked.

Then I discovered this page.  This worked.  Thank you!

# David said on 18 May, 2010 07:49 PM

Thanks for the solution - this did the trick!

# Jack said on 02 June, 2010 10:24 AM

This method  works on my CanScan Lide 30. Thanks!

# Mattia said on 04 July, 2010 03:47 PM

you are simply great!

# Keith McCombe said on 11 August, 2010 05:13 AM

Thanks Jeff - fixed my cannon 4200F which stopped working (unable to open TWAIN source) One of my recently installed apps. must have corrupted the PATH variable. Now working OK. Thanks again.

# Ajay Sharma said on 11 August, 2010 03:12 PM

Thank you Jeff! This fixed the issue with my canoscan 656u not working on Windows 2003. I had to use Windows 2000 drivers for it, but that's besides the point. Putting the Twain_32 folder in Path variable was the solution for me.

# Jeffrey Crawford said on 15 August, 2010 12:33 AM

I tried the above solution for my FB630u Canoscan on a Vista system.  It worked like a charm.  Thank you so much.

# Marco said on 15 August, 2010 04:11 PM

Thank you very much!

# BruceL said on 17 August, 2010 05:55 PM

Thanks very much, Jeff!  Also works with the 4200F on Windows 32-bit Vista Home Edition.

# Fredrik said on 25 September, 2010 02:49 AM

Thank you so much! Finally got the scanner working!

# Jani said on 27 September, 2010 11:45 AM

Many thanks!

# Ross said on 29 September, 2010 08:25 PM

Absolute legend!!  Why this isn't simply found when updating drivers etc on the Canon site.

# Nikos said on 05 October, 2010 01:13 PM

Thanks a lot! Worked fine for LIDE 35 on Vista Ultimate 32bit.

# Chris said on 11 October, 2010 05:55 AM

Brilliant.  This fixed it for Windows 7 64 Bit.

Looks like Acronis backup software install messed up the path variable.

Due to the wide range of apps that seem to mess up the path settings I wonder if its a windows bug or if the canon install doesn't format it correctly in the first place....eg perhaps it needs a trailing ;

# Iain said on 24 October, 2010 02:50 PM

Alas, it didn't work for me. I've got a Canon LiDE 500F scanner running under Vista which keeps giving me this TWAIN error message. I've un-installed all of the software, reinstalled it, updated it from the Canon website, but to no avail. Your suggestion looked a good one, but alas, it doesn't work in my case.

# Ashleigh said on 24 October, 2010 07:36 PM

Thanks a million! Solved my issue--thought I was going to have to finally upgrade scanners but now I can hold out longer.

# Pete said on 01 November, 2010 08:42 AM

Unfortunately, it didn't work for me... It tells me that "Release the lock switch, detach I/F cable and reconnect. Scanner driver will be closed." than it gives the TWAIN error. I read something about a black-and-white bar near the front controls which the scanner uses for aligning, and that the problem might be that it is warped somehow. Anyone knows something about this problem, or preferably, to fix it? I have a lide 25...

# Dieter said on 07 November, 2010 05:43 AM

Thanks, exactly what I needed. The problem seems to be omnipresent.

# Jan said on 17 November, 2010 05:08 PM

Thanks, for advice. :-)

# jesse wu said on 10 December, 2010 08:53 PM

great.

fix my problem. Thanks

# Howard Fong 914 Porsche said on 05 January, 2011 06:38 AM

I feel unlucky. This did not work for me after upgrading some Intel WIFI drivers. The "path" details you mention arleady have some Intel thing in it so I added what you said seperated by a semicolon but still get the error message. what do do next? Thanks in advanced. Am using W764-bit. Should I use 64 instead of 32 in the text? Also, I have the LIDE25

# Howard Fong 914 Porsche said on 05 January, 2011 06:44 AM

OK, I'm bad. Want to update for future readers with same specifics (W7 64bit and LIDE 25). I had input the wrong LIDE model in my path edit. Left it at 32 for 32 bit and the scanner works. Whooo hooo! Hooray!

P.S., should I change to 64 intead of 32 in the text edit? Are the drivers really 64 bit? I installed the latest complete software package from the Cannon U.S. support site. The description says its for W7 64 but if one tries downloading the driver serprately it is only for 32 bit. Can Cannon be any more bad at support?

# pfomich said on 09 January, 2011 05:16 PM

Jeff,

Mine is LiDE25 and I did exactly as you suggested but no luck yet. Any other suggestions. Thanks a bunch.

# David said on 16 January, 2011 02:03 PM

Did not work.  I'm still getting

"Release the Lock Switch, Detach the USB

cable, and Reconnect. The scanner driver will close"

and

"Unable to open TWAIN source. Please check the connection and start again"

This is on a LiDE 20 scanner

# Elbert Waller said on 30 January, 2011 09:24 AM

Thanks! Did work for me.

# Brian Savvas said on 03 February, 2011 12:36 AM

Thanks, it worked for me on a Canoscan LiDE25 after two days lost and Canon unable to help.

# Ken said on 09 February, 2011 07:35 AM

This is simply awesome. It works fantastic for my CanoScanLide25. Thanks a lot. I have been figuring out for the whole night.

THANKS

# Ray Jones said on 14 February, 2011 04:49 PM

I tried this and it did not work.  I have been using the scanner for several years and have been able to reload it and use it successfully on a new Vista system.  Suddenly it stopped working.

The existing path appears quite strange to me and is as follows:

C:\Program Files\CommonFiles\ArcSoft\Bin;%SystemRoot%system32;%SystemRoot%;%SystemRoot%\System32\Wbem

ArcSoft is the photo software that I am working with.  But it won't work directly from the CanoScan Toolbox either.

I tried adding C:\Windows\TWAIN_32\CNQL30 directly after adding the semi-colon and then by adding a semi-colon and a backslash.  Neither worked.

Any other ideas?

Thanks for helping

# Scottt said on 19 February, 2011 01:56 AM

Thanks you so much for the tip.  My Canon LiDE 500F worked fine for years and one day I got this TWAIN error.  I tried uninstall a few times but it still didn't fix the problem until I found the solution on your site.  Good sharing!

# Darth Continent said on 03 March, 2011 11:03 PM

Thanks, this worked for my Canon LIDE 25!

Windows 7 Ultimate is my OS, and although I couldn't get Canon's own CanoScan Toolbox to work, I was able to get Windows 7's scanner driver operational with the above. The only difference was my TWAIN file path, I had to add this to my PATH setting:

C:\Windows\twain_32\CNQL25

After a reboot, my CanoScan LIDE 25 is working once more.

# vichet said on 13 March, 2011 09:46 AM

thanks you very much. I tried many method from many forum but cannot make my scanner work. But this time, the problem solved.

# Eve said on 15 March, 2011 09:34 PM

Help, I think I messed up the entire path line accidentally. How can I fix it? Do you have the entire text that should be there??

# Walter said on 31 March, 2011 12:15 PM

Jeff,

Thanks so much for posting this fix.  It was not obvious why the scanner would have failed after working for a couple of years.  I just wonder, how did you find this out?

# Rowan said on 20 April, 2011 03:20 PM

Many thanks Jeff,  

My daughter in Australial mailed me with the problem, I contacted my son (the wizz kid) in Sweden & he sent her the link. the fix is  done and now I get the scanned documentation I needed.

# yulia said on 21 April, 2011 11:17 AM

thanks a lot!

i can't find any infomation about the problem in Chinese! So i arrive at  here through Google, and it works! 太好了！

# Warren said on 23 April, 2011 11:53 AM

Thanks - you saved me from buying a new scanner!

# Tarun said on 24 April, 2011 09:43 PM

Thanks a lot. I've had this scanner for a couple of years - and encountered this problem for the first time today (of course, when I needed it to work urgently). Luckily, I ran across your solution first and am back up and running now.

Once again, Thanks a million!

# Sune said on 02 May, 2011 04:47 AM

Thanks a lot from Copenhagen, Denmark

# Rob Butler said on 03 May, 2011 04:52 PM

Thanks for your instructions - got my Canon scanner working a treat!

# Sreedhar said on 14 May, 2011 09:08 AM

Thanks for the information so much...

# David said on 15 May, 2011 05:16 PM

Fantastic, worked like a charm on my Windows 2003 Server 64-bit. Like with many others, this problem just happened recently with the CanoScan working great before. In any event, the solution worked super well for me. Thanks a ton!

# Tim said on 16 May, 2011 02:04 PM

Thanks Jeff, luckly found this page quickly LIDE70 fixed in no time on both XP and Vista computers!

# Rob said on 16 May, 2011 02:45 PM

Jeff, you Sir, are a Gentleman and a Scholar, a million thanks, excellent walkthrough and worked an absolute treat, once again many thanks.

# Joe said on 19 May, 2011 01:41 PM

Wow! Brlliant fix! Thank you!

# MANOLIS XANIA said on 26 May, 2011 05:43 AM

YOU ARE THE BEST!!!!!!!! THANKS WORKING FINE NOW!!!!!!!!!!!!!!!!!!!!!!!

# Gary Davis said on 29 May, 2011 11:24 AM

Thanks, it worked for me. Not sure how it worked over the previous years! I updated the drivers from the Canon site but that did not help. The Path addition was the needed fix.

Gary Davis

Webguild.com

# Rob Callaghan said on 31 May, 2011 09:22 AM

I have just had this problem. File CNQ4803 is in the C:\Windows\twain_32 folder.

I just tried to edit the path, but only got as far as Control Panel and System and Security.

I have no advanced settings tab in my system and security menu.

Re-installing the programme does not help as I continue to get the same message.

# James said on 04 June, 2011 03:26 PM

You are the man!

# Tresy Kilbourne said on 04 June, 2011 11:15 PM

Man, you are a lifesaver. My 4200F stopped working after upgrading to Win 7 SP1. I was on the verge of throwing out the scanner and buying a new one. Thanks.

# morgan said on 11 June, 2011 04:28 PM

Canon driver self-installs in c:\canon not c:\windows\twain.  I copied it to \windows\twain and pathed it . . . nothing different

# Tamas said on 17 June, 2011 05:45 AM

Thanks so much!

I have a Canon Lide 25, my path to twain is:

c:\Windows\twain_32\CNQL25

After putting it into path variable scanner get working again!

# Josh said on 17 June, 2011 04:57 PM

This path worked great with my CanoScan 4200F: C:\Windows\twain_32\CNQ4200

Thanks!

# Anthony L said on 17 June, 2011 10:50 PM

Running Vista Home Premium. My CanoScan N1220U, about 10 years old now, is only used it a few times a year. Like everyone else has experienced, it just stopped working! Added the folder to the system path and it started working again. Thanks!!!

I can't imagine that something just took it out of the path. I doubt it was ever there to begin with. Must have been some system configuration change or other service pack that mucked up Twain, but what do I know. Regardless I'm glad its working now, saved me a trip to Staples. Thanks a million!

# elliphant said on 28 June, 2011 03:47 PM

Apologies if this is redundant, I didn't read through the entire thread. Win7x64: use Canoscan Toolbox v4.9, not v5.0. For some reason the newer one doesn't work, but the older one does (5.0 might work on 32-bit, don't know). Install the driver first (SetupSG.exe) (look for 8400fvst6410231a_64en [32en for 32-bit, I would think]) then install the Toolbox (csbwin4932en). You might have to use Jeff's path variable trick; I did that before all the rest and I didn't go back and test without it, so YMMV. Once everything is done you will need to reboot before everything will work. A good tool for testing and troubleshooting is to download Irfanview, which has Twain and scanning tools under the File menu. Enjoy!

# elliphant said on 28 June, 2011 03:52 PM

Geez, forgot to say that I'm using an 8400f - procedure might work for other older models too.

# Will said on 30 June, 2011 05:10 AM

I just want to say thank you.

My canoscan lide 70 works like charm.

# Oscar said on 30 June, 2011 10:18 PM

I have a canoscan 4200F and it worked before I installed W7 (x64) SP1 but not since. I tried this and it doesn't work.

# Rob said on 04 July, 2011 11:30 PM

Hi Jeff. Thanks very much. I have spent hours with unistalling and reinstalling the Canon drivers and software to solve this problem which made no impact. I tried your solution on my XP system and it worked perfectly. Thanks again.

# Maria said on 06 July, 2011 06:12 AM

Thank you so much!!!

My Canoscan Lide 60 is working again and your instruction made it fast and simple. Great!

# Anton Staykov said on 06 July, 2011 06:40 PM

Great helpful post!

# Selton BFK said on 08 July, 2011 02:47 PM

Muchas gracias! me ahorraste mucho trabajo!

# Jakub said on 11 July, 2011 04:02 PM

damn. this left me two months without home scanner after a reinstall to Win 7. Thanks a lot for the trick.

Why can't the installer add the path itself. Or why is it necessary to have it in the PATH variable in the first place.

But I gess we can be lucky Canon provides 64 bit drivers for such old products.

# Kurt Johnson said on 27 July, 2011 05:50 PM

Another satisfied customer.

PATH add was my answer for an LIDE35 on Windows 7 (32-bit).

Thanks, Jeff!

# JB Leep said on 29 July, 2011 05:18 PM

I have been doing this sort of stuff a long time, and when I come across someone who gives such a precise and effective answer, I find it truly awesome.  thanks so much for your efforts.

# Marek from Czech said on 30 July, 2011 08:25 AM

Thanks for your help!

# Melissa said on 31 July, 2011 11:45 PM

Thank you, this work fantastically! I can stop swearing at my scanner now...

# Vladimir said on 04 August, 2011 08:09 AM

Thank you, it worked for me. Only the puzzle is why the problem appeared. It worked for more than one year without any problem.

# Joseph said on 07 August, 2011 01:17 PM

Hi Jeff,

Thank you very much for the clear and concise instructions, it helped to fix the error quickly.

Thanks,

Joseph

# Boyd said on 15 August, 2011 11:26 AM

Thanks mate, got my Canon LiDE 25 working again.

# Geza said on 19 August, 2011 12:20 PM

Many thanks for your information.

You are great as China! :)

I did it, following the your steps and got a working LIDE25 scanner.

I've almost lost all of my hair.

Thanks again

Géza

# heppa said on 23 August, 2011 03:01 PM

Thanks! This fixed also my Canon F4200 with Windows XP with same problem.

# AB said on 26 August, 2011 06:27 PM

Thank you so much!

# Green Forest said on 03 September, 2011 10:32 PM

Thank you so so much! By your advice, I've fixed my Canon LiDE 60 with Windows 7 with the same problem. Now I am enjoying the great performance of my scanner again!

I'm so grateful to you!

Forest

# Gianfranco said on 11 September, 2011 07:30 AM

thank you very much

# Michelle said on 13 September, 2011 10:06 AM

I used your info to fix my old Canon LiDe scanner. It was great to find this solution on the internet.  It really works!  Thanks for keeping this info out there for us to find.  

# Rita said on 13 September, 2011 07:56 PM

Try downloading MP Navigator XP for PDF's,

instead of Canoscan Toolbox.

I had the same problem. I just wanted my Canoscan LiDE 90 to scan in PDF format. Toolbox kept insisting it was 'unable to select the twain source'. So added it my path, reinstalled, etc etc.   Nothing worked.

Then downloaded MP Navigator EX.   Presto !   It's basically the same thing as Toolbox.   I had forgotten that that's what I was using on my old computer !   It's so similar to Canoscan Toolbox that I didn't clue in until several wasted hours later.  

Found it at:

www.canon.ca/.../serviceDetail

# neeta said on 15 September, 2011 04:49 AM

hi I have a Canoscan 5200F and I get the same message about TWAIN source. I did everything as indicated above but the toolbox still does not function! so what can I do now??

# Magnus said on 15 September, 2011 08:58 AM

Awesome! Finally I can scan with my FB630U with Vista and Picasa.

thanks for the info!

# BAN ANG said on 15 September, 2011 04:02 PM

Thank you very much for the info. I was going to buy a new scanner. Imagine that.

You just saved me some bucks

# RJ said on 16 September, 2011 10:39 AM

Thanks for the blog entry. Solved my problem.

# Problems Scanning with Canon Lide under Windows 7 / Windows 7 x64 | Just trying to make it all work… and then stay that way said on 16 September, 2011 04:17 PM

Pingback from  Problems Scanning with Canon Lide under Windows 7 / Windows 7 x64 | Just trying to make it all work… and then stay that way

# Jonathan Ezor said on 21 September, 2011 11:25 PM

As with the others, thanks so much! {Jonathan}

# Wolfgang said on 22 September, 2011 12:44 PM

Cool, thanks a lot. Took me a hour to get the Scanner running on x64.

# Eric said on 24 September, 2011 09:25 PM

Solved on win7 x64!

# Jan Bart (De Bilt in the Netherlands) said on 28 September, 2011 04:05 PM

Thanks Jeff for the information regarding the "path". Unfortunately it did not work but together with the comment from Elliphant on June 28: use canoscan v4.9 in stead of v5.0 I got my scanner 8400f working again.

# Piotr said on 29 September, 2011 10:42 AM

Jeff - Now it works ! :) THANK YOU

CanoScan 4200F & Win7 x64

# Jackie said on 01 October, 2011 12:46 PM

Hey there, this didn't work for me unfortunately, I have a Canon N670U and it suddenly stopped working about a month ago saying its unable to open TWAIN source, do you have any other ideas?  Thanks, Jackie

# Tibor said on 02 October, 2011 05:17 AM

Hi Jeff,

Thank you so much. This helped me with CanoScan 8400F.

Thanks,

Tibor

# Bernhard said on 10 October, 2011 09:04 AM

I was unlucky - didn't work - still: many thanks.

# Jeremy said on 13 October, 2011 07:47 AM

Hi Jeff,

Thanks! Quick easy fix! Canoscan LiDE 60

# Matrix said on 14 October, 2011 07:52 PM

Big thanks Jeff! CanoScan 4400F. Used to work fine for years. Suddenly stop working today. Don't know how the environment variable got changed. Windows update maybe?

# Richard Collette said on 16 October, 2011 07:32 PM

I wish I had found this years ago.  Finally my Canoscan 8400F works and with both Canoscan Toolbox and Picasa as well.

# Aleksandar said on 22 October, 2011 09:30 AM

You are magnificent! Working perfectly now.

# Cas said on 26 October, 2011 02:38 AM

Thanks Jeff - it didn't fix my CanoScan D1250U2F problem but your instructions were really easy to follow and made me feel less frustrated nevertheless!

# JOG said on 02 November, 2011 09:28 AM

Thanks Jeff it fixed the problem on my CanoScan LiDE 600F

cheers,

john

# Canonlide25 said on 06 November, 2011 07:47 AM

YES IS FIXED, this works on Windows 7, no in XP

En XP no se arreglo nada, pero en Windows7 si funciono

MUCHOS GRACIAS jaja

Thanks a lot!!!

# CheekyKelz said on 06 November, 2011 07:53 AM

Hiya Jeff, I was wondering if you could post that entire pathway plz because I accidentally deleted the pathway instead of just adding to it. I went to press the arrow on my laptop and pressed wrong button grrrrrrrr, could you help plz thanks

# Jeff Widmer said on 07 November, 2011 05:06 AM

Hi CheekyKelz,

Unfortunately the PATH variable is specific to your computer; as new applications are installed, new paths are added.  At a minimum it will include this:

 %SystemRoot%\system32;%SystemRoot%;

-Jeff

# behind said on 15 November, 2011 09:23 PM

Bravo !!! tanks Jeff

# Dave Sellers said on 16 November, 2011 12:15 PM

Yep, worked for me too! Cheers Jeff.

# Kevin Rothwell said on 16 November, 2011 12:53 PM

Thanks Jeff! Your kindness in posting this solution is STILL helping people out! After installing a new Canon multi-function printer, my old Cannon 9950F scanner stopped working with the error described. (It's got a long scanning bed, so I want to keep it.) It now works again after following your instructions. Thanks again!!

# Nate said on 16 November, 2011 03:55 PM

Thanks! That fixed it for me too!

# Nathan said on 17 November, 2011 10:55 AM

I could Kiss you! you absolute legend!

# Markus said on 17 November, 2011 11:13 AM

Thanks! :-)

# Kit Yung said on 23 November, 2011 09:07 AM

Sorry it didn't work for me.  Mine is a CanoScan 4400F and my OS is VISTA 32.  I added the path as suggested but the result is the same

# Henny said on 24 November, 2011 01:58 PM

No luck for me, but awesome this has worked for so many people. I am trying to setup CanoScan LIDE 50 on Windows Vista Home 64 bit. Very annoyed at Canon for being so unenvironmental - imagine all the scanners that just go to landfill because people can't figure this stuff out.

# Jovandeka said on 25 November, 2011 03:11 PM

Thanks for your help!

Jeff for President!!!

# Jake said on 02 December, 2011 05:32 PM

You just saved my bacon.

# Otto said on 06 December, 2011 10:57 AM

Great help. Thank u so much

# man in motion said on 19 December, 2011 03:18 AM

Thank you very very much! Made my day!

# Josef said on 28 December, 2011 10:01 AM

Thanks so much,

after reading so much different threads and spendings HOURS of other solutions (including a complete Factory re-set),

this worked liked nothing ...

# Alexander Avidan said on 29 December, 2011 01:43 AM

Excellent!!!!!!!!! Worked great.

Thanks a lot.

# Ehoa said on 29 December, 2011 12:16 PM

Many thanks! Don't know how this PATH got lost...

# Sebastian said on 03 January, 2012 11:27 AM

Thanks Jeff, our Lide 60 is back working again on Windows 7!

# Rick said on 04 January, 2012 05:33 PM

I have a Canon CanoScan 5200f

I Did exactly as you instructed...I also double checked and did a restart... but unfortunatley the exact same problem persists...'unable to select TWAIN source'

I have Windows7 64bit...i first downloaded and installed driver from CNET then found the tool box exe elsewhere and installed in 2-steps...perhaps this is the issue as when using the toolbox it always asks to select source after which the issue arises...any thoughts on this one???

Cheers

Rick

# Jeff Widmer said on 04 January, 2012 09:48 PM

Hi Rick,

Try downloading the latest version of the Windows 7 64-bit Canon software from Canon's website: www.usa.canon.com/.../support.

-Jeff

# Francesco said on 05 January, 2012 06:36 AM

Thanks for the help, saved my day with my CanoScan 5200F

# Haymo said on 05 January, 2012 11:43 PM

thank you so much for this!

# Aaro from Finland said on 06 January, 2012 01:56 PM

Thanks a lot Jeff

This was great and solved my problem immediately

# Rick said on 09 January, 2012 06:11 PM

Hey Jeff

Cheers for your reply.  The link you provided lists every other scanner in Canon's series except for the 5200f...perhaps the 4200f series listed is the driver to be used?

In any case the driver I had initially downloaded from CNET was successfully installed and I believe it was the right 5200f driver.  So are you suggesting that my issue (described in my first comment) can only result from having the wrong driver installed?

Penny for your thoughts?

Cheers

Rick

PS - The comments of gratitude found here on your blog attest to the help you're providing many people so please add me to that list also...thanks very much ;-)

# Long Zheng said on 12 January, 2012 12:38 AM

Thanks. This fixed the problem I was having with my Caonn MP800 and the MP Navigator software as well. It would just give me a "Scan failed" every time.

I eventually figured out it was a TWAIN problem by looking at %temp%\twain.log which had "CloseServer - Why Can't We Find The Thunker Window?" but didn't know how to fix it.

Lo and behlold, I added the C:\Windows\twain_32\MP800 directory to my PATH and it works again!

# Jeff Widmer said on 12 January, 2012 06:05 AM

Hi Rick,

It looks like the 5200F is a European model only which possibly could be the problem with installed a US version of the software (but that is just a guess).  If you still are having problems try this link from the Canon UK downloads: www.canon.co.uk/.../CanoScan_5200F.aspx

-Jeff

# Shavaj said on 15 January, 2012 03:37 AM

Many thanks. Path variable was the issue

# richard p said on 16 January, 2012 06:17 AM

Windows 7 64 bit and a Canon 5200F. I had this problem, and went nack to the Canon 4.9 Toolbox, and with your path set, - it worked. Thank you.

# Chris said on 17 January, 2012 01:53 PM

Win7 64-bit and a CanoScan LiDE 25. You saved my life, thank you!

# Darrel said on 20 January, 2012 08:36 PM

Thank you so much!

# Catherine said on 22 January, 2012 02:00 PM

Windows 7, 32 bit, Canoscan Lide 90. Used to work fine until now, when I had to replace my HD on my computer (it also doesn't work w/my new netbook, Windows 7 starter 32 bit). I think it might have to do with the new 5.0 version - I had been using 4.9 or earlier, I think, with no problems.

I looked for the C:\Windows\twain_32 folder and found two CNQ folders in there (2411 and 2412). I tried inputting the path for one, then the other, but neither worked. Should I put in both?

# David P. said on 23 January, 2012 07:55 PM

It worked!! Better than some of the other solutions that are out there. Thanks so much.

# kaneXtreme said on 27 January, 2012 06:35 AM

Wow. I was reinstalling my driver everytime i come across this problem. Now its fixed forever! Hopefuly.

Thank you so much for this wonderful article! ;)

# Delbert said on 03 February, 2012 06:55 AM

That workded. You're a saviour.

# LIN said on 04 February, 2012 12:45 AM

Hi I need your help!!!

I'm using canoScan 8400F.

I followed your instruction but the window still pop out:

Unable to open TWAIN source

Please check connection

Then restart toolbox

Any advise?

# Olaf said on 04 February, 2012 06:49 AM

Thanks Jeff - this method works fine, but only after I added a backslash \ at the end of the path.

# Phillip King said on 06 February, 2012 04:39 AM

Thanks for the info!  Much appreciated and saved me the hassle of the usual uninstall / reinstall / repeat cycle!

# Helenmary Cody said on 06 February, 2012 12:59 PM

Thanks for posting this! I've wasted a LOT of time trying to figure out why my scanner no longer wants to scan and this fixed it in less than 5 minutes. I wish I had found it sooner.

# jhen said on 07 February, 2012 10:07 AM

Thanks for posting this. It was really a lot of help. At last I am able to successfully scan my document.

# Toprope said on 09 February, 2012 04:47 AM

Thank you so much, it works!!!

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