Okay, if you're using 102, export is easy. Just click tools>export and it creates a complete profile backup. To restore it, just click tools>import. Nothing could be easier. However, if your profile is huge (multiple gig, that isn't advised because this process uses zip files and there have been problems reported with profiles in the 2 gig plus range).

The other option is a few extra steps but not complex. Assuming you have not moved profile to a custom location (few do) First, exit Thunderbird. This is IMPORTANT. If Thunderbird is running, the backup will be incomplete and that is why some automatic backup software produces backups that cannot be used. Next, in Windows Explorer, My suggestion is to copy everything in the folder named 'Thunderbird', e.g., c:\users\<yourid>\appdata\roaming\thunderbird The advantage here is that this includes the pointer Thunderbird looks for when starting, which means it can be copied readily to a new PC and run immediately AFTER first installing Thunderbird on the new PC.

Finally, if you moved profile elsewhere, confirm exactly the location of your profile. That is done by clicking help>moretroubleshootinginformation, scroll to 'Profile Folder', click the box 'open profile' and you will see the exact location of profile. I suggest writing that down for future reference. Next, exit thunderbird for reasons already explained. Now, in Windows Explorer, highlight that folder and copy it elsewhere. .

On your question, the backup makes a copy of everything: account info, message files, filters, addressbook, passwords, everything.

Thank you, David. You have been very helpful.

You are most welcome. If you would, please mark this solved so it is removed from the open issues list. Thank you.

First, exit Thunderbird. This is IMPORTANT. If Thunderbird is running, the backup will be incomplete and that is why some automatic backup software produces backups that cannot be used.

David, the add-on "ImportExportTools NG" must have some compensating mechanism for not exiting Thunderbird before/when a backup is run. Please see this thread:

Local Folder Backup -- Automated process https://support.mozilla.org/en-US/questions/1317339

The poster, @nn4zz, posted fantastic screenshots that show how ImportExportTools NG can be used to automate the back-up process.

Also, when I manually run ImportExportTools NG to make a backup, there is no way to both run it and first shut down Thunderbird before running it. Best I can do is first take Thunderbird offline before running the backup.

So how does ImportExportTools NG run a backup with Thunderbird still open (using either the automated or manual "backup" process)?

My comment was in reference to using Windows File Explorer (or other external tools, such as backup software, e.g., Acronis). I do encourage people, regardless of how they do backups, to test the backup to ensure it works. I have routinely seen people posting that their backup did not work. Regarding importexport utility, I have no doubt that, since it works within Thunderbird, that it would have the capability and opportunity to ensure no problems - but I would test anyway.

Thanks for your reply.

I still wonder how it works? It must put Thunderbird on pause or take it offline, or something like that...