I’ve tried downloading a few assets from the recent sale, and I get an error “Opening file failed” where the details indicate that the .unitypackage file can’t be accessed by the process because it is being used by another process. I’ve used the Resource Monitor in Win10 to see what other process it could be, but it’s just Unity.exe.

Unity Version 2019.4.12f1 Personal
I’ve temporarily stopped DropBox sync and my Antivirus real time protection, but got the same results.
I’ve tried using the default asset store download directory, and I’ve tried turning that into a symbolic link to a different drive. The results were the same.
Clicking “Try Again” appears to refresh the error dialog box, indicating that it’s still in use. Resource Monitor confirmed that Unity.exe is still the only process using it.
I think one of the partially-downloaded demo scenes is missing resources due to this error, but am not certain because I haven’t had a fully successful download yet. Some of the downloaded assets appear to at least partially function as expected.
Any ideas on getting past this error?
Thank you.