A 90Gb profile folder sounds somewhat excessive. I have 40,000 message in my inbox for a 4gb footprint. although with all accounts and some ancient junk, my profile is still less that 20gb. But that is not the issue today.

Goto the troubleshooting information on the help menu, click the show button for the profile to open file manager/explorer in the profile folder that is in use. Is it the one you have copied your data into? By far most issues relate to the profile in use not being the one expected. Even more so as profile name no longer are Default.

Not sure where I got the 90G. Most of my saved profiles are between 2 & 3 G and 50k files. I have been using TB since the beginning and have upgraded my desktop computer at least 5 times and never had an issue moving my profiles to the new computer.

I double checked the folder from the 'trouble shooting information' and that is the correct folder that I am using.

Before you did the Win10 reinstall - what version of Thunderbird were you using ? When you had to reinstall Thunderbird program, what version did you reinstall?

When moving to new PC or performing a OS reinstall - I would advise you backup/copy the Appdata/Roaming/'Thunderbird' folder as it contains everything. I would also advise you reinstall the same version of Thunderbird as you were previously using and run once, but do not create accounts. Exit Thunderbird, access Appdata/Roaming folder and delete the default 'Thunderbird' folder, then paste the backup 'Thunderbird' folder into the 'Roaming' folder. Start Thunderbird.

When doing Win10 fix - did Windows create a 'windows.old' folder in C: drive ? If yes, then you may discover all data backed up in that folder here:

• C:/Users/user name/Appdata/Roaming/Thunderbird

and If you have not installed same version as previously used... Copy that 'Thunderbird' folder Exit Thunderbird if it is running. Uninstall Thunderbird.

Access * C:/Users/user name/Appdata/Roaming folder Delete the 'Thunderbird' folder. Paste the copied 'Thunderbird' folder into the 'Roaming' folder. Download and install the version of Thunderbird that you were using prior to fixing Win10 OS.

I always keep TB updated, so I am not sure what version I was using prior to WIN 10 re-install. I have the latest ver 78.11 now. Could have been a recent previous version. I will work on that.

Thanks for the info.

--Mike

Hopefully, you may find a 'windows.old' folder with full copy of old Thunderbird. In the 'profile name' folder, there is a file called 'compatibility.ini' which can be opened using Notepad to read it. In the backup copy of original 'profile name' folder , that 'compatibility.ini' info would tell you what version was last used.