In Windows Thunderbird updates are automatic by default. This is not ideal in situations like yours, where upgrading to the very latest too quickly exposes you to regressions that may affect your experience.

I've seen this issue come up a few times in the last few days. I'd suggest reverting to a previous Thunderbird version for now.

Regarding the latest update, you can uninstall the current Thunderbird version via Control Panel > Programs and Features and reinstall a previous version, download it from here:

• Version 31.0
• Version 24.7

Click on the type for your OS. eg: If using Windows select 'win32' then select the language eg: en-GB = English british then download the .exe file

You can customize automatic updates behavior, however, it's under Tools > Options > Advanced > Update.

My suggestion would be to set it to Check for updates, but let me choose whether to install them., specially if you depend on email for critical / important business or personal matters.

Hi Fabian,

Thank you for your input. It was at least good to know that although I had a real problem, it was not due to an error on my part. I have reverted to version 31.0, and the reported problem has disappeared (along with another one which I discovered later, which appeared to be interfering with the processing of browser links in incoming e-mail).

I have also changed the Thunderbird update flag to the "check but let me decide" setting, as in this case I obviously don't want any further updates applied until there has been time to sort out these problems. In general, however, I am in two minds about this setting. After all, the release notes would hardly have said "and by the way, this update will screw up your signature settings", so I would probably have gone ahead and applied it anyway. I would hate to end up in a situation like that of Windows 8.1, where everyone dithers for weeks before deciding whether it's safe to install an "important" update!

By the way, is there an accepted method for drawing attention to what appear to be bugs in Thunderbird?

I am glad to hear that your installation is now functional again.

I agree it's hard to pass the opportunity to get new shiny features, fixes and of course security fixes when a new version is out. However, with something as critical as email it's also hard to justify not waiting at least a few days / weeks / months and being more conservative. I encourage you to keep an eye on future release notes and news, and perhaps even bug reports if you have the time.

Of course coming here in my opinion is the easiest, fastest way to bring up issues and Cget a workaround, while we (the Mozilla support volunteers) raise developers attention to it.

BTW thanks for marking the solution, This will help other users with similar problems find the solution more easily.

Thank you for contacting Mozilla Support!