Forum der Gemeinschaft Thunderbird

I have been a Thunderbird user for many years and have just received the following error message which I haven't seen before. Will appreciate any advice as to how to rectify the issue. "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mailbox."

I am a long-time user of Thunderbird. My PC is reinstalling Thunderbird. I am being asked for a password. I do not have one. There is no provision to reset my password. Please help.

I have an old(er) Thunderbird file - we were not able to get the system running so we just plugged in the hard drive and zipped it (not with Thunderbird, just zipped the raw files - see attached) and I have tried all three methods that Gemini spit out to me (#3 looks like what I have seen on the forums here) and the bext I can do is get the first message to pop up (out of about 500+) and can't see the others. Using Thunderbird on the new machine and also tried the ImportNG tool as well. I can't loose this collection, very important. Although the old machine does not work, I still have access to the hard drive if I need more "stuff" off of it. Not sure what the old version of Thunderbird was but the box was last used in Jan 2019 and setup originally around 2008. Thank you in advance for your assistance.