Today, after months of working with few issues, the Qt Visual Studio Tools extension for Visual Studio 2019 stopped working on my computer. I have uninstalled and reinstalled it using the "Manage Extensions" interface in Visual Studio, and I have used the Qt Maintenance Tool to uninstall and reinstall the "MSVC 2019 32-bit" and "MSVC 2019 64-bit" portions of the Qt 5.15.0 that I am using. That hasn't helped.

The error message starts with "The 'Vsix' package did not load correctly", and it tells me to look inside ActivityLog.xml for more information.

ActivityLog.xml contains "SetSite failed for package [Vsix]Source: 'QtVsTools' Description: Could not load file or assembly 'Microsoft.VisualStudio.Threading, Version=, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified." (As well as some other stuff.)

So is QtVsTools not working because it isn't finding a specific version of a threading library? What can I do to get it working again?

Thanks for any help.