I have been getting an error message when trying to update my Thunderbird Email client. After it updated, it was asking me to restart Thunderbird, after restarting I was greeted with the following message.

"Software Update Failed. One or more files could not be updated. Please make sure all other applications are closed and that you have permission to modify files, and then restart Firefox to try again."

I found the solution was to stop Spybot TeaTimer running. To do this, run Spybot, click on Mode, and check Advanced Mode. Click on Tools, then Resident, then untick TeaTimer.

Once you have done this, check for Thunderbird Updates, then restart Thunderbird when asked. This should now work as supposed. You can then restart TeaTimer to resume your protection.

I found the solution on this forum post.