The first rule of making backups is to ensure that you also have a means to restore from the backup. All those GB of data are worthless if you cannot make use of them.

With Outlook you can just add an old pst file into it and browse its contents. The nearest equivalent in Thunderbird would be to add an old profile via the profile manager. You could then choose which profile to open when starting Thunderbird. There are add-ons which make switching between profiles easier.

The main drawback of this is that while Thunderbird can host multiple profiles, they are mutually exclusive. You can only have one open at a time and so transferring data between them can be a tedious process of opening the old profile, exporting, switching to your current profile and then importing.

Alternatively. it's possible to run two or more instances of Thunderbird, each working on a different profile. You need to use command line switches to get this to work. A small number of users do this as routine, thereby ensuring separation between, say, work and personal email accounts. Note that the motivation is to keep things separate, so I can't say this makes it easy to use data from an alternative profile.

Another point to consider is whether you are archiving or making backups. Your process is fine for a backup because in the event of a failure you just replace a damaged profile by the most recent backup. So the issue of whether or not you can open and read data stored in the backup is somewhat irrelevant.

If you want to archive old data and be able to browse it then the usual recommendation is to export it to an easily read format. Options are eml, txt, html or even pdf (ugh!) files. I would warn you that the resulting mess of files is rather hard to organise and search.

Zenos said

The first rule of making backups is to ensure that you also have a means to restore from the backup. All those GB of data are worthless if you cannot make use of them. With Outlook you can just add an old pst file into it and browse its contents. The nearest equivalent in Thunderbird would be to add an old profile via the profile manager. You could then choose which profile to open when starting Thunderbird. There are add-ons which make switching between profiles easier. The main drawback of this is that while Thunderbird can host multiple profiles, they are mutually exclusive. You can only have one open at a time and so transferring data between them can be a tedious process of opening the old profile, exporting, switching to your current profile and then importing. Alternatively. it's possible to run two or more instances of Thunderbird, each working on a different profile. You need to use command line switches to get this to work. A small number of users do this as routine, thereby ensuring separation between, say, work and personal email accounts. Note that the motivation is to keep things separate, so I can't say this makes it easy to use data from an alternative profile.

I'm not going to fib and tell you I understand this answer. Can folders from Thunderbird be imported into Outlook?

Secondly, I have no idea what this statement means: ''With Outlook you can just add an old pst file into it and browse its contents.

Can you help me by clarifying with me a little more?

Zenos said

Another point to consider is whether you are archiving or making backups. Your process is fine for a backup because in the event of a failure you just replace a damaged profile by the most recent backup. So the issue of whether or not you can open and read data stored in the backup is somewhat irrelevant. If you want to archive old data and be able to browse it then the usual recommendation is to export it to an easily read format. Options are eml, txt, html or even pdf (ugh!) files. I would warn you that the resulting mess of files is rather hard to organise and search.

How would I archive old data and how would I export it to an easily read format?

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I installed that import/export tool. If I just right click (RC) on one folder I can use the option to "Export all messages in the folder" and then another context menu opens to the side where I can select format, like EML.

But I want to do this for the whole account, not just one folder. When I RC on my account I don't get the option where I can choose the format. It exported all folders in my account, but in unreadable form.

Please work out whether you want a backup or an archive. They are two very different things, serving different purposes. What you're making right now would serve very well as backups. They are pretty much useless as archives.

Since Thunderbird stores messages in precisely the format they have when they arrive, often requiring some form of decoding to render them as readable text, there should be no expectation that the message store would be human-readable. Your messages may be mime-encoded, base-64 or html. None of these will make sense viewed in their raw form, as stored by Thunderbird.

If another email client works better for you then by all means use that email client.

Zenos said

Please work out whether you want a backup or an archive. They are two very different things, serving different purposes. What you're making right now would serve very well as backups. They are pretty much useless as archives. Since Thunderbird stores messages in precisely the format they have when they arrive, often requiring some form of decoding to render them as readable text, there should be no expectation that the message store would be human-readable. Your messages may be mime-encoded, base-64 or html. None of these will make sense viewed in their raw form, as stored by Thunderbird. If another email client works better for you then by all means use that email client.

Is there any reason why I can't have both?

The profile is not designed or intended to be human-readable. So it fails as an archive, but provides exactly what you need to restore data after an accident.

You could browse an old backup profile by opening it with Thunderbird, by using its profile manger to select the old profile.

https://support.mozilla.org/en-US/kb/using-multiple-profiles

It's common for similar programs to choose different methodologies. The Thunderbird approach is to store a message exactly as it arrived, then decode. render and format it when you open it to read it. That way you can always go back to the exact same original data, which is useful when diagnosing problems and essential if the data is needed for forensic purposes.

Other email clients may do a one-time decoding and store the decoded data, so the mail store is likely to be easy to read. But you would then have no traceability back to the original message, just a cleaned refined filtered copy of it.

Some mail clients may do both, but then you're storing each message twice. That's wasteful.

Ok, guess I'll let this go. Thanks for your time and trouble.