Outlook VSTO Add-in not visible in Outlook

Question

I have an Outlook Add-in(under development) which was working fine on my old system. I decided to migrate to a new system(for better performance), when I have done so(IN DEBUG MODE), I saw that after some time the Add-in is not visible in Outlook(neither in COM AND disabled window).

Specifications I am using:

• System type is 64-bit OS, x64-based processor

• Microsoft Visual Studio Community 2019 Version 16.5 with .NET framework 4.7.2

• Microsoft Office 365(16.012730.20144) 32-bit

Troubleshoots I tried:

1) Checked Build Office solutions , for verifying all items are generating and working properly.

• Registry entry is generating correctly.
• VSTO file(bin/debug) is getting installed successfully(when I manually double click that)

2) Troubleshooting by Event Viewer:

No error's related to Outlook(as a source).

Possibly related error's:

i) Source - DistributedCOM: The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID {6B3B8D23-FA8D-40B9-8DBD-B950333E2C52} and APPID {4839DDB7-58C2-48F5-8283-E1D1807D0D7D} to the user NT AUTHORITY\LOCAL SERVICE SID (S-1-5-19) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

ii) Other Errors are from source PerfNet and NDIS(Which I suppose is not related to this topic)

3) Troubleshooting by Process Explorer:

Their is no outlook Add-in DLL present in process explorer.

4) Troubleshooting by Process Monitor:

I am new with procmon, so just used some basics like, applied a filter with Outlook process name(including registry, file system, Network, process and thread activities). And the results were SUCCESS, BUFFER TOO SMALL, NAME NOT FOUND, NO MORE ENTERIES other. Their was nothing I can relate with my issue.

Other Information

• After this issue, I made a same new project and it worked fine, but the same happened(Add-in not visible) after some time. And I have done this(Created new project) four times till now. What I observed is, when I create a new Add-in with same name, the issue is same, so I have to choose different name every-time.

I am not able to find any error description for this. So can anybody please tell me what is the issue here OR how I can troubleshoot more(with above tools or new one).

Thanks in advance.

Answer 1

If you don't see your add-in listed in the COM add-ins dialog of Office applications, the problem is related to Windows registry keys required. Read more about them in the Registry entries for VSTO Add-ins article.

It seems something is wrong with your add-in registry entries (maybe permissions). And the issue can be related to Windows/Office bitness. Most probably you had another Office edition (bitness) installed on the old system (or Windows).