The profile holds everything, so you are already backing up everything.

If your e-mail accounts will change when you change servers, you probably want to move or copy messages from IMAP folders (if you have IMAP accounts) to local folders first.

If you say more about how you will use the back-up copy after the server change, people here may be able to help ensure a smooth transition.

Thank you so much for your timely answer.

I do use IMAP on all the accounts. The email accounts will not change and I presume I will need the back ups to be imported to my new server so all the emails and data will be available there in the future for Thunderbird to access.

It's difficult to get meaningful answers from either my current host or the one 'm going to as everyone seems to have sent customer service overseas.

Please clarify: if you change to another server, why will the email accounts not need to change? I am not questioning you, but knowing the details prevents people here from giving inappropriate suggestions. Ricks point is valid, as we have seen people switch servers and not realize what they had done until the prior server with all their messages was no longer available. From your post, you already do an automatic backup, whereas thunderbird has no such option. Have you ever restored from that backup? No need to answer, but we also regularly see users attempting to use a backup that doesn't work. Anyway, let us know about the IMAP account. thanks.

You will want to determine whether or not you should copy/move all your IMAP messages to local folders before the server change.

I should have been more precise in my first message when I wrote "if your e-mail accounts will change". I'm thinking these things through for the first time. What's important is probably whether or not the messages on the server will be transferred to the new server. If they will be, I assume that you'll be able to continue as is with the same accounts, even if you have to change the server addresses in Thunderbird.

But I don't know anything about server changes, so I am raising a concern more than I giving advice. Perhaps other people on the forum can help more.

In any case, if you are not certain that everything will function as before, copying messages to local folders is a good thing to do.

Thank you for that! I'm hoping there is and app/program that will copy all the messages to local folders or a remote drive so even if the server change damages/loses some I will have everything locally anyway.

I am talking about copying to local folders in Thunderbird. It is very easy.

I have a lot of local folders in T'bird, so you think that if I make a local folder and move all my inboxes emails etc that will solve my problem?

For each folder, right click on the folder name. Use the drop-down menu to copy it to the local folders "account", not to a specific folder.

Since you have many folders, you may want to do this in the file system instead of in Thunderbird. I have seen that operation fail, and I don't know why. It should be reliable. So I tend to suggest copying within Thunderbird.

How many folders do you have?

Please ask if you want guidance in the file system.

For the special folders of inbox, drafts, etc., you will have to create a folder in the local folders account for each folder and copy the individual messages to a destination folder.

Timing of the copying is important to make sure that you copy everything right before the server change.

Just to add a reminder to OP: if you have 'synchronization&storage pane for the account set to sync all regardless of age, and have all folders checked for offline access, then the messages are, technically, already on the PC. Steps that Rick are proposing are various ways to COPY them to a safe place. As I am a bit paranoid, I also click File>offline>download prior to the COPY as my final check that all IMAP messages are on PC.

I have one domain with 3 users and 3 domains with one user each and probably 50 folders under "Local Folders'.

I guess I was hoping that someone knew of a program that was dependable and simple that would back everything up for me routinely and then I wouldn't have to chance losing something because I screwed up copying folders.

I've seen programs on the net, but have no way of knowing which one is dependable and which are not not. I know some have annual fees but I am a one man business not an 'enterprise' with unlimited budget.

On that, I suggest you check around a bit. I use IDRIVE for $3 a year. Important, VERY important, that you set the backup to run at end of day when thunderbird is not running. Otherwise, you introduce the possibility of having a corrupt profile than cannot be restored. Also, you never explained the server issue. If your email host is changing servers, then I don't see why you need to do anything. My inference from your posts here is that the email account will not change, but the server will and that you have to move the account. I have never seen or heard of this. I only bring this up a second time to ensure we are giving you the help you need. Possibly, if you shared some details, that may clarify, such as the email host, the domain of your account. And, that's just a suggestion.

Macintosh comes with a back-up program that can run automatically. I assume that Windows does too.

The add-on ImportExportToolsNG has some automated back-up options that I have not used.

No problem. My email hosting company has been charging me $20.99 a month for the last few years for email only and they just upped the cost to $70.00 a month with no warning. So When I called they said basically tough sh#+ so I'm changing server companies. I hate it that you can't speak to an American any more with so many of these companies but I guess that's life.

Just to add a reminder to OP: if you have 'synchronization&storage pane for the account set to sync all regardless of age, and have all folders checked for offline access, then the messages are, technically, already on the PC. Steps that Rick are proposing are various ways to COPY them to a safe place. As I am a bit paranoid, I also click File>offline>download prior to the COPY as my final check that all IMAP messages are on PC.

Good points, David.

I try to be very conservative with data. Captchas, if I were changing e-mail service providers, I would make a back-up copy of everything before doing anything else, then copy everything manually to local folders in Thunderbird, then make another back-up copy of everything.

good suggestion! Thanks

I have not read all of this topic, so my apologies if it is duplicated information.

I see a lot of folk talking about making direct copies of files and folders from the file system to make local copies and backups. This is all good but as David has said what you get depends on some Thunderbird settings and your own ability to copy the correct file. Unfortunately my experiences over recent years is there appears to be a large body of folk that can not cope with file copies from a file manger or command prompt. Generally they mess it up. So I try to avoid suggesting same.

Them there are the vagaries of IMAP and what is stored locally in the profile and what is stored in the cache which none of the file copying will capture as the cache is considered expendable. In the case of store apps, I can not even find a clear and simple way to find the profile that is used, let alone copy anything from it. Even opening the profile folder from the troubleshooting information fails

So I always recommend the import export addon and have done for more than 10 years, Rick says he has not experience with it, but it is a particularly good Swiss Army knife of export options that was originally written by an Italian guy (Kaosmos). Because Kaosmos gave up on Thunderbird addons Christopher Leidigh took over the code after Thunderbird 68 and rewrote it for Thunderbird mail extensions (the new and at the time somewhat contentious new addon interface) and added the NG for NEW Guy to the name so there should be no confusion about which works with what versions of Thunderbird.

One if the major issues with IMAP export is you really do not know if the body of an email is stored locally or not. You also do not know if the local copy is the most recent version of that email. While they rarely change, they can. The import export tools addon takes the guess work out of the export as it validates each email against the server copy before it exports it and downloaded anything needed to perform the export. It makes the process significantly slower that "just copying a file" but it is also a much more guaranteed outcome. For my archives I would be tempted to use it myself, but I realty don't have one these days. Email from this forum comprise a lot of my email and if I lost the lot I would loose very little really.

Then there is the issue that most folk ignore and it is a significant one. Thunderbird may open and update a file many times a minute. The only time you can be sure it is not being written to is when Thunderbird is not running. Backups of open files have a long history of not being valid with corruption being common. I saw some mention of an apple baclup tool, but I doubt it backup open files. Most don't

Now the format you export mail to is important and folk unfortunately have a tendency towards the offered HTML and PDF formats. Not because they are any good, but because they are familiar. As an archive they are really not a good solution. The real choices are EML and MBOX. They are defacto standard mail formats. EML is the format that is transmitted across the internet. What arrives at the mail server as new mail is basically an EML text file. Not an email at all really but a text file. Context is everything

The second defacto format is MBOX. Few outside of email circles have heard of it, but at it's heart is is a just single file representation of a pile of EML files one after the other. (I simplify for convenience. I don't think the email dividers used are all that important here.) It is also recognized as an archive format by the US library of congress. https://www.loc.gov/preservation/digital/formats/fdd/fdd000383.shtml

Now to the practical. Hundreds of thousands of individual EML file are a little unwieldy in a file explorer context, but most that have viewer capability will recognize the file type and attempt to render the mail content. This looks attractive but if it was that good, why do we have a mail client at all?

MBOX files are really just a storage format (they are also Thunderbird's native storage format) but each can contain whole folders of mail and they are readily imported into a number of email clients, not just Thunderbird. So they make for a good archive storage format and are my recommendation.

To summarize although it can be slow I strongly recommend the use of the add-on as it reduces the risk of errors and validates what it exports where file copy simply can not. It can also iterate through nested folders, exporting hundreds for folders as a single job.

Now to the caveat no one has any regard to at all. Every mail provider has daily data limits and they all vary. Google's can easily be reached buy those trying to import hundreds of thousands of emails from an old account to a new one. They often appear in this forum complaining their copy just stopped or just stalled, others can only upload a limited number before stopping again and that is usually caused by antivirus products slowing things to a crawl and in some cases actually crashing the connections. The addon appears to handle these situations in a some what more robust manner on export, but it refuses to import to an IMAP account at all. Local folders only.

A final word, if changing hosting services DNS will have to be updated to reflect the move. This is not instantaneous, the DNS system replicates and that takes time, possible a day to get to some of the servers in the more remote corners of the internet. The big providers like Google, Microsoft,Yahoo and Amazon along with others on the internet backbone get updated almost in real time, but the DNS server is Johns tire shop might take a day so email they send in that interim may will go to the old provider. It is important to not close up shop with the old provider for a time to allow the dust to settle and any mail that is coming to actually arrive. There needs to be an overlap period. I would suggest at least a couple of days with the wears on all over the place disrupting things.