Error HRESULT E_FAIL has been returned from a call to a COM component

Question

In Silverlight 4 app; what does this error mean?:

\"Error HRESULT E_FAIL has been returned from a call to a COM component.\"

It

Answer 1

I encountered this same error after installing VS2019 and trying to open a large solution (20+ projects), with both vcxproj and csproj projects, that target VS2015. The csproj all loaded fine, while the vcxproj all failed with the OP's error. Deleting the .vs folder did not work.

What did work was setting VC++'s "Fallback Location", under the "Browsing Database Fallback" settings.

Tools (menu)
-Options...
--Text Editor
---C/C++
---Advanced
----Browsing Database Fallback
-----Fallback Location

I set mine to D:\VC++\v16. Where I use v140 for VS2015 and v141 for VS2017. Also set "Always Use" and "Do not warn".