Unrecognized Tag Prefix

12 posts, 0 answers
  1. Daniel
    Daniel avatar
    18 posts
    Member since:
    Apr 2011

    Posted 25 Nov 2011 Link to this post

    Following a crash of Visual Studio I'm experiencing an issue where all of my Telerik tags on my aspx pages have blue underlines.  Mousing over the underlined tags reveals the following error message "Unrecognized tag prefix or device filter 'telerik'".  I've also lost Telerik intellisense.  Does anyone know what the solution is? I've tried removing and re-adding all of the Telerik references and bin files.  This did not fix the problem.

    Note, prior to Visual Studio crashing I had made only a few minor text edits to the project...nothing that major that I would expect could have caused these problems.  I'm using VS 2010.
  2. Princy
    Princy avatar
    17421 posts
    Member since:
    Mar 2007

    Posted 27 Nov 2011 Link to this post

    Hello,

    Make sure that you set the TagPrefix as telerik.
    ASPX:
    <%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %>

    Thanks,
    Princy.
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  4. Daniel
    Daniel avatar
    18 posts
    Member since:
    Apr 2011

    Posted 30 Nov 2011 Link to this post

    I did that already.  It doesn't solve the problem.  What else could cause a problem like this?
  5. Princy
    Princy avatar
    17421 posts
    Member since:
    Mar 2007

    Posted 30 Nov 2011 Link to this post

    Hello,

    Take a look into the following forum thread.
    unrecognized tag prefix or device filter 'telerik'.

    Thanks,
    Princy.
  6. Daniel
    Daniel avatar
    18 posts
    Member since:
    Apr 2011

    Posted 06 Dec 2011 Link to this post

    I attempted the fixes listed on that page.  Unfortunately none of them solved the problem.  Any other ideas?
  7. Sebastian
    Admin
    Sebastian avatar
    9934 posts

    Posted 07 Dec 2011 Link to this post

    Hello Daniel,

    I think that the information from this documenattion topic will help you eliminate the issue you are currently experiencing.

    Regards,
    Sebastian
    the Telerik team
    If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed now
  8. Daniel
    Daniel avatar
    18 posts
    Member since:
    Apr 2011

    Posted 08 Dec 2011 Link to this post

    I've just tried everything on that page and still Visual Studio is not recognizing the telerik tag prefix.  What else could the problem be?
  9. Zÿm
    Zÿm avatar
    26 posts
    Member since:
    Jun 2010

    Posted 15 Dec 2011 Link to this post

    I also tried these solutions, none of them works for me too. 

    I started to get this error, after i have upgraded it to a new version. I am not installed telerik on computer. 
  10. Zÿm
    Zÿm avatar
    26 posts
    Member since:
    Jun 2010

    Posted 15 Dec 2011 Link to this post

    Ok, found the answear. The Telerik.Web.Desing was of older version than Telerik.Web.UI;
    In short, version mismatch in Telerik.Web.*.dll.
    Still i am getting errors in Design View
  11. Bryan
    Bryan avatar
    1 posts
    Member since:
    Jul 2011

    Posted 13 Sep 2012 Link to this post

    I had a similar issue, and the solution was to replace all Telerik files in the Bin folder with the newer versions (not just Telerik.Web.UI.dll).  These files are typically located in your c:\program files\telerik\[release version]\Bin[.net version] folder.
  12. Map
    Map avatar
    1 posts
    Member since:
    Jan 2009

    Posted 31 Dec 2013 Link to this post

    Where I should write this prefix?
  13. headPropellerHead
    headPropellerHead avatar
    9 posts
    Member since:
    Jul 2007

    Posted 20 Oct in reply to Bryan Link to this post

    I never could find the Telerik.Web.UI.dll in the GAC, in spite of running the update and "make a telerik website" wizards repeatedly.  Finally, I was able to find where the files were downloaded by Telerik (C:\Users\<user>\AppData\Roaming\Telerik\Updates\Telerik_UI_for_ASP.NET_AJAX_2016_3_1018_Dev_hotfix\Bin40).  I copied them to the bin folder of my project, made sure the references were set to the copy in the bin, and it worked.
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