As I updated from 78.9 to 78.10 without any issues at all, I think you will need to explain what you are wanting to express as I and I wold guess others have nothing but a simple restart of Thunderbird in the update process to mark it as having occurred..

Fixed problem myself. Thunderbird did an update and when restarted came up with the error posted. Searching files found that the file xul.dll had been updated that day. Went to my backups and copied the file to the thunderbird directory and program started without a problem. Issue resolved for now.

This question has been locked because the original author has deleted their account. While you can no longer post new replies, the existing content remains available for reference.