Hello, Depeds if you use IMAP protocol not, but if you use Pop3 maybe you lost some emails, try archive or backup your data before reset the Thunderbird: *[https://support.mozilla.org/en-US/kb/archived-messages Archived Messages] *[https://support.mozilla.org/en-US/kb/profiles-tb#w_backing-up-a-profile Backing up a profile] *[https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer Moving Thunderbird Data to a New Computer] After try create a new profile: *[https://support.mozilla.org/en-US/kb/using-multiple-profiles Using Multiple Profiles] Then restore you data: *[https://support.mozilla.org/en-US/kb/profiles-tb#w_restoring-a-profile-backup Restoring a profile backup]

Can you post a crash ID? https://support.mozillamessaging.com/en-US/kb/Mozilla-Crash-Reporter#w_viewing-crash-reports Re-installing Thunderbird does not remove your profile, unless you tell it do do so. Having said that, re-installing seldom solves problems with the profile.

genewit, please post your crash ID