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VSTO Addin not showing/loading RRS feed

  • Question

  • Hi

    Hoping someone can help here I am banging my head against a wall.  Not sure if this is the right forum, but I have a VSTO that is packed into an msi via a wix installer.  I have a 64 and 32 bit version.  I am using Office 2019 64bit.

    The installer works fine, we can see the addin in the registry, but it won't show up in the addins view and when I try to add it I get the message that it is not a valid office addin.

    Does anyone know if there is a known issue?  Is there a specific way in which I should be creating the installer?  I know it's not much to go on, but it's all I have :)


    Friday, June 26, 2020 8:45 AM

All replies

  • OK, true to form as soon as you post for help on a forum, you fix it.

    Here's what had happened, although the installer had installed it into the correct folder and added the registry item.

    The click once trust behavior in registry was all set to disabled and my certificate, even though I installed it into trusted root, just wasn't working.

    I used the setting for How to: Configure the ClickOnce trust prompt behavior

    I can't link to it ironically I'm not trusted yet, but searching for that will find it.
    Also when I got another user to check, who was having the same problem, they did not have those registry settings at all.

    Double clicking the vsto file installed it correctly and it's now working.  So it seems that the installer was in fact not installing the vsto correctly, no idea why that would be, if anyone knows, please let me know.

    • Edited by Karl Walls Friday, June 26, 2020 11:12 AM
    Friday, June 26, 2020 11:09 AM
  • Hello,

    but it won't show up in the add-ins view

    It seems the add-in windows registry keys were added to a wrong branch. The branch is different depending on the OS and Office bitness. 

    Make sure that you did all the steps described in the Deploy an Office solution by using Windows Installer article. 


    profile for Eugene Astafiev at Stack Overflow, Q&A for professional and enthusiast programmers

    Friday, June 26, 2020 1:04 PM