TB 9.x partial update: unable to remove directory: tobedeleted

On October 02, 2019 an anonymous blog commenter reported something that appears to be an update problem. From https://blog.torproject.org/comment/284256#comment-284256:

Anonymous (not verified) said:
partial update is not clean; logs:
NS_main: unable to remove directory: tobedeleted, err: 41

boklm said:
Where/when do you have this error?

Anonymous (not verified) said:
Win 10 x64