App-V Shell Extensions Broken in Windows 10 1903/1909

Shell extensions for App-V packages are broken in Windows 10 1903 and 1909. Previous OS versions are OK, even when fully patched. Microsoft are aware and working on a fix!

Here’s an example when trying to use the context menu from 7-Zip. The menu still appears but generates an error when trying to use it:

7-Zip Error

Note that you can also see this error on 1809 and previous if you enable App-V for the first time then try to use this functionality before rebooting.