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VS 2013 Pro Update 5 - Unrecognized tag prefix or device filter "asp"

    Question

  • Hi Experts,

    IntelliSense in aspx-Pages (SharePoint-Application-Page) stopped working for asp Controls.

    <%@ Register TagPrefix="asp" Namespace="System.Web.UI" Assembly="System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %>

    Can be reproduced when creating a new empty SharePoint-Projekt (Farm-Solution 2013) and adding a Application-Page.

    No 3-rd-Party-Add-Ins involved.

    This has been working in the past and is now failing for unknown reason.

    What i checked so far:

    • Cleared the AppData\Roaming\Microsoft\VisualStudio\12.0-Folder of my user
    • Unloaded Project and reload
    • Readded Reference to System.Web.dll

    Any Help appriciated, with Kind regards, Ronny

    EDIT: THe asp Tagprefix is working in ascx-File of a User-Control (SharePoint-Visual-WebPart).

    What I also have done: Re-Apply Default VS-Settings and Restart VS. Error persists in aspx-Pages.

    Monday, April 24, 2017 3:50 PM

All replies

  • Hi Ronny, 

    Two possible ways to fix it for you to try:

     Close Visual Studio -> Delete the <ProjectName>.v12.suo file. -> Reopen solution.

    or 

     someone also tried the below steps and worked

     Resetting your settings or importing previously exported, working settings, and restarting Visual Studio  worked:

     Tools > Import and Export Settings... > Reset all settings.

    Hope it helps. 

    Best regards, 

    Fletch

     


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    Thursday, April 27, 2017 8:44 AM
  • Hi Fletch,

    thank you for your quick Response. I tried that already with no avail. Error persists.

    Any other idea?

    Best Regards, Ronny

    Monday, May 01, 2017 5:39 PM
  • Hi,

    you could have a look at the following:

    1. Delete or rename the folders: C:\Users\<your users name>\AppData\Local\Microsoft\VisualStudio\12.0 and C:\Users\<your users name>\AppData\Roaming\Microsoft\VisualStudio\12.0

    2. Repair visual studio 2013

    3. Unrecognized tag prefix or device filter 'asp' in VS2012

    Best regards,

    Joyce


    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Tuesday, May 02, 2017 9:00 AM