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Excel is Attempting to load my VSTO add in Lookin in the Office directory RRS feed

  • Question

  • Having an issue with loading of my VSTO addin, which does not load when running from an non-admin user. Using the Fusion logs, I can see that Excel is using the LoadFrom context\ for the non-admin user:

    === Pre-bind state information ===
    LOG: DisplayName = Extensibility, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
     (Fully-specified)
    LOG: Appbase = file:///C:/Program Files (x86)/Microsoft Office/Office16/
    LOG: Initial PrivatePath = NULL
    LOG: Dynamic Base = NULL
    LOG: Cache Base = NULL
    LOG: AppName = EXCEL.EXE
    Calling assembly : Excel Plug-in, Version=1.0.0.0, Culture=neutral, PublicKeyToken=62c05bdc2eac9643.
    ===
    LOG: This bind starts in LoadFrom load context.

    This causes Excel to use its installed folder to attempt to resolve the assembly location:

    LOG: GAC Lookup was unsuccessful.
    LOG: Attempting download of new URL file:///C:/Program Files (x86)/Microsoft Office/Office16/Excel Plug-in.DLL.
    LOG: Attempting download of new URL file:///C:/Program Files (x86)/Microsoft Office/Office16/Excel Plug-in.EXE.
    Note: This Plugin does not install into the GAC.

    When the admin user opens Excel, it uses the default context:

    === Pre-bind state information ===

    LOG: DisplayName = Extensibility, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

     (Fully-specified)

    LOG: Appbase = file:///C:/Program Files (x86)/Excel Plug-in/

    LOG: Initial PrivatePath = NULL

    LOG: Dynamic Base = NULL

    LOG: Cache Base = NULL

    LOG: AppName = NULL

    Calling assembly : Excel Plug-in, Version=1.0.0.0, Culture=neutral, PublicKeyToken=62c05bdc2eac9643.

    ===

    LOG: This bind starts in default load context.

    What privileges missing for the non-admin user make Excel use the LoadFrom context? Is there a way to externally force Excel to use the default Load context when starting?

    Thanks.

     


    Monday, August 21, 2017 8:30 PM

All replies

  • Hello,

    How do you publish the add-in? Do you deploy it by using ClickOnce or Windows Installer or other third party tools? Does the issue exist for all add-ins? Could you share detail repro steps here?

    Regards,

    Celeste


    MSDN Community Support
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    Tuesday, August 22, 2017 4:43 AM
    Moderator
  • Hello Celeste,

    The Plugin is installed via an MSI (windows Installer) file. The issue is known to only exist for this one instance: an admin user installed the Plugin, a non-admin user is attempting to run the Plugin.

    We are unable to reproduce anywhere but this one situation and believe it related to differences in permissions.

    As Excel is responsible for loading our Plugin, is there any way to know why it is using the "load From" context rather than the Default Load context? Is there a way to force which context it uses?

    Thanks for your response.

    Lawrence

    Tuesday, August 22, 2017 5:11 PM
  • Hello,

    I don't think we could force Excel to change which context it uses.

    Could the add-in run in other computers? Could the add-in run for admin users in this PC? What error would you get when you load the add-in for a non-admin user? Do you check the loadbehavior in the registry?

    Please check if the following links would help:

    My Office Addin does not Load!

    https://stackoverflow.com/questions/4668777/how-to-troubleshoot-a-vsto-addin-that-does-not-load

    Regards,

    Celeste


    MSDN Community Support
    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.

    Wednesday, August 23, 2017 6:33 AM
    Moderator