I booted Windows 7 Professional and opened the latest version of Thunderbird on July 14. Almost all of my profile had been deleted. The only thing that remained was my Account Settings. All of my emails, folders and subfolders, address book addresses, selected Options (Menu Bar, Mail Toolbar, etc.) and Add Ons were deleted, including my ImportExport Tools add on that I use to back up my profile by exporting a copy to my external hard drive and the cloud. With the exception of the information still retained in Account Settings, it was as if Thunderbird had reset my profile and reverted it to its original state when I first downloaded the software. Thunderbird version 52.9.1 was released to channel users on July 10, four days before my copy went haywire on July 14. This is the version that deleted my profile. The release notes say it is compatible with Windows 7. Could this new version have a bug that caused it to delete my profile? If so, how do I report a bug? Fixing Thunderbird was a time consuming hassle. Because Thunderbird deleted all of my emails, it did not recognize copies of previously downloaded emails that had been retained on my ISP's POP mail server, so when I used Thunderbird to log into my ISP, Thunderbird downloaded about 400 emails, most of which I had previously downloaded and dealt with, mixed in with emails that I had downloaded and not dealt with, and emails that I had not downloaded. It took hours to sort through this email by email, even though I only had to go back through emails dated on the date of my most recent profile backup. Also, since I was unsure what would happen to emails that I wanted to save after I restored my profile --the restored profile would obviously not include them so they would be deleted, and my ISP could not say for sure whether the restored profile would recognize they had not been downloaded from their server to that profile, and if the profile would download them again or not-- I backed up these emails one by one, by forwarding them to a second email address not connected to a Thunderbird account. Because Thunderbird deleted my ImportExport Tool add on, I could not import my backed up profile. After an hour of fiddling I located the hidden App Data\Roaming\Thunderbird\Profiles folder, deleted the profile folder in it, and replaced it with my backed up profile folder, which restored everything when I relaunched Thunderbird. The restored profile recognized the emails in my POP mail account that it had not previously downloaded and downloaded them, including the emails that I had saved by forwarding them to the separate email address not connected to a Thunderbird account. So I deleted all of the saved emails at the separate address. I'm not a tech geek and this process took about half a day to figure out and do. The only good thing I can say is that I back up religiously and was able to restore my profile. Any ideas what caused this? If it is a bug in the new version, how do I report this?