Is this a POP account? If so, and if she downloads messages and filters (or moves) to various folders, then that can't be replicated on the server. If this is an IMAP account, she could set up the folders on the server and work with the online folders. Knowing the account setup will help in giving a more precise response. Also, knowing whether her folders are under "Local Foldes" will help, as some people use IMAP and still make local copies.

@david: it's an IMAP account. In theory she could set up the folders on the mail server, but it's a big job (create a few dozen folders and then move all the mails to the correct folder?). I'm looking for a "lazy" solution where the sync would replicate the existing folder organization on her client to the server. The folders are not local folders. I experimented using my own mail account. When I installed Thunderbird, there was only an inbox and a few other folders. My "saved mail" folder from my mail server was not visible in the client. Then I turned off the restriction to sync only subscribed folders and tadaa.. Al my saved mail folders appeared in Thunderbird. Then I messed a bit with it by adding and deleting folders at both ends and by moving a few mails around between folders. Every change was nicely replicated in both directions. But that doesn't answer my question. I don't want to run the risk to loose the folder structure in Thunderbird when I turn off the sync restriction on her PC.

Okay, I'm confused. You say they are not local folders and also not folders on the server. On your question, if sync'd, IMAP protocol will give priority to the server and delete the local messages. I am also puzzled on how she managed to set the folders up. Rightclicking an account and creating a folder puts it on the server, so she must have taken extra steps somehow. To confirm the folder locations, I suggest rightrclick and select 'properties' and see if it is a disk address (e.g., mailbox://c:/....) or a pseudo URL address (e.g. imap://....)

@david: You say they are not local folders and also not folders on the server. Correct. The "saved mail" folders only exist for the e-mail account in the client. The mail server has no "saved mail" folder. All mails on the server are still in the inbox. if sync'd, IMAP protocol will give priority to the server and delete the local messages. That's what I'm afraid of. You seem to confirm that since the folders don't exist on the mail server, all folders (and their content) on the client will be deleted and the old mails will be shown in the inbox. That's what we don't want. Correction: since we have some "illegal" situation, there's probably no way to predict what will happen to the mails themselves if the folders are deleted on the client because that folder didn't exist on the server ??? I am also puzzled on how she managed to set the folders up. Rightclicking an account and creating a folder puts it on the server, so she must have taken extra steps somehow. Don't know how she managed to get there. I did a little experiment (on my own computer): I enabled "sync only subscribed folders" and re-started the mail client. Instantly the "saved mail" sub-folders in the client disappeared. Nothing changed on the mail server. I expected that the folder "saved mail" would also disappear on the client, but that didn't happen. Only the sub-folders disappeared. The I created a new (empty) folder "TEST". The folder then appears on the server. So, you are right that she somehow managed to organize her mails in folders on the client without replication on the mail server. But this is the situation today. As part of my experiment, I moved a mail from my inbox to the TEST folder on the server. This is instantly replicated on the client. Next I delete the TEST folder on the client. On the client, the TEST folder is moved to the recycle bin (including the mail which is in that folder). On the mail server, the same thing happens. Conclusion: 1. there seems to be no "lazy" way to replicate folders created on the client back to the server, if those folders don't exist on the server. A replication attempt will remove the folders (and their content) on the client if they don't exist on the server. My friend would no longer be my friend... 2. The current situation is inconsistent with the normal behaviour of Thunderbird. Any change you make on the client is normally replicated on the server, regardless of the server setting in the client for syncing subscribed folders. 3. Check the folders properties: will have to wait. She's sick and I don't have remote access to her computer (She doesn't understand how to install TeamViewer). I tried this on my own set-up and the synced folders all have "imap://..." as you say. I'll come back once I've had a chance to look at this on her computer. 4. Given the current situation and the reluctance to "manually sync" the client folders to the server, my best option for a "lazy" solution is to back-up the user's profile file to Google Drive or something along that line.

I concur. Her best backup approach is to back up what is on the PC. You're a good friend to work so diligently to assist her. I'm sure she appreciates what you do.

Thanks for your support ;-)

Hi @ ghersschens, read it all today (11/13/23). May it be that your problem is still not comprehensively solved?

Thouht about it. First thing is, find your Profile folder on your machine and make a backup from it. On Windows make a 7z (or do "send this folder to ..." and chose zip) at C:\users\john\AppData\Roaming\Thunderbird. On Linux do "tar c ~/.thunderbird | pigz -c > opensuse.thunderbird-20231113-001.tar.gz" . These zipped archives will freeze date and times as well as permissions so they will give you a true snapshot of the day. If you do another one on the same day choose *-002.tar.gz ... . Restore: (1) mv ~/.thunderbird /tmp/ and (2) tar xfz *.gz .

Now you're safe and friends will be friends. However, avoid mismatches of server vs client folder structures. Create new test mails to yourself with subject=test1, body=msg1 on the internet (server). subject=test2, body=msg2 locally on your TB client, see what happens. Good with your syncs? Find "Archive message" buttons on server vs client, press them, see what happens. Mails 1, 2 should "reunite" in Archive/2023/test{1,2} mails more or less. Create subfolders Archive/2023/A (server) */B (client), move test1 > A (do it on internet==server) , test2 > B (do it on TB==client), see what happens. Good with your syncs, again? Be creative, see how far correspondences can go, create deeper subfolder levels (how many levels deep has your friend created previously).

Another avenue, also install TB beta when you already use TB release. TB beta is VERY reliable (99%) and its profile folder will reside withing the same ~/.thunderbird folder (linux) or */AppData/Roaming/Thunderbird (Windows). Operating both at the same time can give you immediate feedback how sync is operating betwenn server <--> client(s). When first connected with TB beta, it might download the complete inbox from the server into TB beta's Inbox, so choose wisely the right point in time when to add another TB profile to your investigator's toolbox. Probably your problem can be completely solved without a TB beta.

That's all for now, what do you think, tell me if you feel an approach like that might inch you further to the finish line.

Good luck, Regards, U.S.

Hi Uwe, thanks for your tips. I'll first talk to my friend (when she' better) to find out how on earth she managed to get her TB out of sync with the server. The procedures you describe all test if client and server do properly sync. They do. My concern (as you can see in previous posts) is that when I turn off the restriction to sync only subscribed folders, the client will sync the server folders with the client folders and since the server is the master and doesn't have any folders, all folders on the client will disappear. What's probably the least risky way to see what really will happen: - make a backup of the TB client profile and store it in a safe location - turn off the sync restrictions in the TB client profile and see what happens - if the folders are replicated back to the server (which I don't expect): party time ;-) - if the folders on the client are deleted: restore the TB back-up profile and keep making back-ups from time to time to avoid loosing the folders and mails in TB if the PC's HDD crashes. What I can't fathom at this point: assuming that the folder on the TB client will be deleted by syncing with the server, the mails contained in those folders are also deleted (to be more precise: moved to TB's recycle bin). On the server the same mails are still in the inbox (server doesn't have those folders). What happes to those mails? Will they be synced again and show up in TB's inbox?

I already tried creating and deleting folders on my own account on both ends (client and server) and the changes are always correctly replicated by the other side. I just can't get client and server out of sync.

I messed a bit more with mails and folders of my own mail account to see if I could create a discrepancy between client and server, but it takes quite a few (unlikely) steps to get there: - delete a folder on the client -> folder is also deleted (= moved to recycle bin) on the server - move the mails from the deleted folder back to the inbox on the server -> nothing happens on the client (!) - move the deleted folder on the TB client back to the "saved mail" collection -> same happens on the server, but now the folder on the client still contains the old mails (syncing failed in the previous step), the folder on the server is still empty (mails there were moved from the recycle bin to the inbox) - move the old mails which used to be in the folder + aa few newer mails from the inbox back to the empty folder on the server - TB and server are now in sync

To be honest, this is far-fetched and unlikely to be the cause of my friend's situation. She doesn't mess with her mailbox. In fact she hardly ever goes to the web client to check her mails on the server, let alone move mails around. She always uses TB to access her mails.

Hi @ ghersschens, it's appropriate to be cautious. So, we're up for next steps.

What we know by now is that we can trust the sync mechanism both ways server <---> client. Next, we may not forget that working with mails from the mail web app within a web browser is a client, too. So we already have two clients working, one in the browser, the other one is TB. One of the clients is out of sync (browser) the other is in restricted sync mode (TB). So can we go from here just by pure reasoning and logic? Let's see.

When we are not connected to the internet and we write some mails and move received mails locally in and out of folders, create new ones and change the overall situation within TB , what is - at least - supposed do happen when we regain internet access at a certain point later on ?? It would be off the tracs if the server god just would invalidate our work and kill our new messages we wanted to send once internet is back again, right? So, without the presence of severe bugs, as soon internet is back on, the client situation is going to be mirrored on the server, that is what should happen, everything else would kill the whole point to have cloud sync, right?

Because of that scenario of what should happen in the absence of bugs it is not wholly correct when you say the server is the master, you see where this is going already? It is more a thing of the right timing. If something happens on a client, the server will be informed of it, only then the server will regain its master status somewhat because all other clients now are able to download (aka "sync") the new situation from the one and only server. So maybe your fears that all will be gone is without merits, think about it.

Despite that, we won't let our guards down, not yet. So this is what I would do at this point. Make a copy locally of all mails and folders withing TB local environment. It works exactly as you'd expect from a normal (aka "real") mail account. Even the spam detection works on the local environment, just copy and paste things in spall portions and see how fast TB works on your machine. Do it with internet turned off. When you are finished with the copy and paste procedure, you should habe the same folder structure under "local" as you have it under "john doe's mails" account.

Now you can turn off the restriction in TB and reopen internet access for your machine. I think sync should run okay, it might take its time but it will sync. If things really should go south, then feed the mails and folder you have mirrored in TBs local environment back nice and slowly back to your real mail account. Piece by piece the mails and folders should be uploaded to the server. This might take its time depending on how much data there is to feed and on your upload speed.

What do you think? Let me know. Regards, U.S.