I did also try Thunderbird in safe mode with add ons disabled and still had the same issue of it hanging. I am on 52.9.1. The situation is now so bad that it is unusable as it hangs almost as soon as I open it.

It's more likely you have an antivirus program acting on email, and when TB updated, the AV program became incompatible with the new version. To see if this is the case, run in Windows safe mode and then see if TB works properly in TB normal mode.

For W10, Shift+Restart, Troubleshooting, Advanced Options, Startup Settings, Restart, 5.

If that doesn't help, and you want to roll back, just install the previous version over the existing version; the profile folder with all user data is unaffected.

If it runs fine in W10 safe mode, disable the email component of your AV program (which is standard recommended practice).

Hi sfhowes, thank you for your recommendation. It turns out to have been something else

I had a look in my gmail help as the email that feeds into my Thunderbird account is a gmail account and tried their suggestion of not downloading files with more than a certain number of emails in them.

This fixed it.

I had changed a save location setting and as a part of this thunderbird was trying to download a file with a large number of emails (for some reason, a huge chunk of my gmail is marked 'Important') and the result was the hanging of the programme. This does seem to have fixed it, but if the problem comes back I will certainly try the above.

I appreciate your help!