Hello this is Guenther, Today on November 23rd, 2020 I migrated my installation of Thunderbird 78.5.0 (64-Bit) from the PC Windows 10 to my laptop also Windows 10. To do this, I installed Thunderbird on the laptop and then replaced the new profile folder with a copy of my old original profile folder. The old profile got the new name. After entering Thunderbird, all directories and email were there. But when I closed Thunderbird and reopened it, Thunderbird crashed. What can I do to secure my e-mails in the long term and use them on a new computer? Who can help me? Thank you! My E-Mail is: [email protected]