Can you try if the crashes also happen in safe-mode? You probably have an add-on installed that is incompatible with 52.1.1 and that is causing the crashes. You can start TB in safe-mode by keeping the Shift-key pressed and starting TB.

If you still want to downgrade, you can download an older version from http://archive.mozilla.org/pub/thunderbird/releases/ and install it. There's no need to first uninstall the newer version. For safety reasons however it is best to backup your profile first.

Thank you! I use very few add-ons and forgot that I had added a google browser add-on. Instead of using safe mode I disabled that add-on and it seems to have resolved the problem. Your prompt answer is very much appreciated!

I'm glad this solved your problem. Can you please give the full name of the add-on that was causing the problem and perhaps also post your crash-id? We can use it to detect what's going wrong and contact the add-on author, so s/he can fix it. You can see the crash-id from Help > Troubleshooting Information and then it's in the third block, under Application Basic and Mail and News Accounts.

Onno Ekker said

I'm glad this solved your problem. Can you please give the full name of the add-on that was causing the problem and perhaps also post your crash-id? We can use it to detect what's going wrong and contact the add-on author, so s/he can fix it. You can see the crash-id from Help > Troubleshooting Information and then it's in the third block, under Application Basic and Mail and News Accounts.

Samkatz, can you reply please ?? Thanks

I was wrong. Turning off add-ons seemed to help at first but only because I had not performed the action that caused the shut down which I narrowed to the following: it happened when I cursored down through unread email with the preview window open. I uninstalled 52.1.1 and reverted back to 45.8.0 and am not experiencing problems with this older version.

Can you please post your crash-id's here? We can use them to investigate the problem… You can see the crash-id from Help > Troubleshooting Information and then it's in the third block, under Application Basic and Mail and News Accounts.