The type 'System.Web.UI.ScriptManager' is ambiguous: it could come from assembly...

25 Comments

• You can add assembly binding redirects to your Web.config to avoid this problem coming back after you delete your /bin files and rebuild. What it does is redirect any requests for the 1.0 version of AJAX for ASP.NET to the 3.5 version.
  
  
  
  
  
  
  
  
  
  
  
  
  

• Problem solved. Thanks for your help.
  

• Also make sure to check C:\Windows\assembly.
  If you see both 1.0 and 3.5, remove one of them.
  

• In our case we're having the same problem on a .NET 2.0 framework based application.
  Can't we just tell IIS/.NET to use the 2.0 version for this application? Avoiding rebuilding everything.
  
  Some extra information: We have applications running on 3.5 and 2.0 which should share the same website but would use different application memory pools.
  

• Hi,
  Thanks a lot!..I found this very useful..
  
  Cheers!
  

• Thank you sooooo much, it worked perfectly. I added the following to my web.config
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

• Tnx... i owe u a lot... mwah!
  

• i try all these solution but the problem still exists
  the solutions i tried:
  
  1- delete all your \bin files and rebuild the application
  2-update my web.config
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  3-remove one of 1.0 and 3.5
  
  C:\Windows\assembly.
  
  
  

• reset the IIS it works sometimes
  

• Thank a lot. It solved my problem OK. Great post.
  

• The following is the error , i am using asp.net 2005
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  The server tag 'asp:ScriptManager' is ambiguous. Please modify the associated registration that is causing ambiguity and pick a new tag prefix.
  
  
  

• Plz Reply at prabodh.bansal2@yahoo.com
  
  Regards
  Prabodh
  

• Oh my god@ very nice
  

• It just a GREAT POST.
  
  Thanks A LOT :))
  

• Thanks a lot.This works nicely.
  

• Comment this line in web config file
  
  
  

• Thanks a lot!
  

• Thank you so much Javier !!!
  

• This blog isn't the whole story. You have to comment out v1.0.61025.0 of System.Web.Extensions and System.Web.Extensions.Design from your web.config. Then you have to remove them using gacutil (in C:\Program Files\Visual Studio 8\SDK\bin folder, if you have VS 2005), or in C:\Windows\Microsoft.NET\Framework\v1.1* folder of that version's .NET Framework Redistributable. You should use quotes around your removal command, like this: gacutil -u "System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35". If you have other things using it, I'd like to see others' responses on how to deal with that part...
  

• Actually I figured out how to remove references, though Microsoft's way of doing gacutil /u /r "System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" FILEPATH C:\WINDOWS\system32\msiexec.exe "Windows Installer" didn't work for me, when it was being held onto by Windows Installer. Had to search for System.Web.Extensions in the registry. Found 2 entries (one for the base, one for .Designs) at HKEY_CURRENT_USER\Software\Microsoft\Installer\Assemblies\Global and removed them. Then I could get rid of the v1.0 DLLs. Hope this helps someone.
  

• Hey i too had the same problem.I went to toolbox,right clicked to add items
  in that i removed the references for updatepanel 3.5 and added 1.0
  similary for script manager and other conttrols.
  after this i added the following line of code on top of aspx page
  

• If you right click on the project,go to property pages remove reference to version 3.5.0.0 , this worked for me.
  

• thank u for your solution .. salved alot of my time :D
  

• Comment this line in web config file
  
  

• Hey there just wanted to give you a brief heads up and let you know a few of the pictures aren't loading properly. I'm not sure why but I think its a linking issue. I've tried it in two different browsers and both show the same results.