Versions prior to v68 did not have a dedicated profile for each installation. As a result, the folder for the Default profile had the .default suffix. Starting with v68, each Tbird installation had a dedicated profile, hence the "-release" suffix for the stable product release version, "-beta" for beta product releases etc. See Dedicated profile per Thunderbird installation

If I want to move my "default-release" profile to a new laptop would I copy <8 character name string>.default-release OVER the empty (newly created) .default or simply paste it into C:\Users\<username>\AppData\Roaming\Profiles (ie so it appears in addition to the .default)

No. You would copy the contents of the "default-release" profile folder to whichever folder is in use on the new laptop; be it a .default or .default-release. The folder names are not very important. What matters most is that you replace the contents of the new profile folder with the contents of the old profile folder. You must therefore identify which profile folder the new laptop is using, Quit Thunderbird (this is crucial), then replace its contents with those from the old laptop. When you launch Thunderbird, it will load the old contents from the new profile folder since it already knows to use the new profile folder.

Thank you so much for your help. This is much appreciated.

So option c is correct.

On the laptop which has the two profiles should I leave the <8 character name string>.default folder (which only contains times.json) in existence please ?

I wasn't aware one could have two instances of Thunderbird on one laptop. I thought you could only have one Thunderbird program on any one computer. Can you have two totally separate instances of the latest Thunderbird on the one computer (which only has one User) ?

This prompts another question: if I want two separate Profiles (basically two separate "Users") - one containing a specific set of email accounts & storage folders and another containing an entirely different set of email accounts & storage folders, can you point me in the direction of an explanation of how to set this up please - preferably using extremely simple language & explaining step by step as I am not a techie !

Thank you again

So option c is correct.

No, because you said, ".default only contains times.json." That means the .default folder is NOT in use and thus is not needed. Contents should go into the folder that is in use, and you already know how to tell via Help-More Troubleshooting Information.

On the laptop which has the two profiles should I leave the <8 character name string>.default folder (which only contains times.json) in existence please ?

Nope. You can delete it since it's not in use. If you compare it to those in use, you'll see the ones in use have a good number of files and folders in them. You should delete this to avoid confusion about which is which and what is required.

Can you have two totally separate instances of the latest Thunderbird on the one computer (which only has one User) ?

I suppose so, I'm not sure since I've never done anything like that because I think it is pointless. Instead, I have multiple profiles used by the same version (latest), with each profile loading in its own instance of Thunderbird. You can manage profiles using the Profile Manager as explained here Profile Manager - Create and remove Thunderbird profiles. On the other hand, having different versions of Thunderbird (for whatever reason), each installed in its own folder and each using a dedicated profile, even if the profiles are clones of each other, make sense because there are noticeable differences between major versions. For instance, you could have v52, v68, v78 and v98 all on one computer running concurrently. I do this a lot when investigating issues reported here, while using beta (for testing) and the latest stable release for mission critical use if beta is acting up.

This prompts another question: if I want two separate Profiles (basically two separate "Users") - one containing a specific set of email accounts & storage folders and another containing an entirely different set of email accounts & storage folders, can you point me in the direction of an explanation of how to set this up please - preferably using extremely simple language & explaining step by step as I am not a techie !

The profile manager is all you need to accomplish this, as explained here Profile Manager - Create and remove Thunderbird profiles. Each profile has its own folder, so each profile user will have their respective accounts and storage folders. Note, however, that it's very easy for a user to launch another user's profile in such a setup, which is something you probably want to avoid hence the need for separate users. A better option would be to have separate non-administrator (standard) Windows user accounts for each user, which will automatically come with their own separate Thunderbird profile that isn't accessible to the other non-admin users.

Thank you for your further response.

I expressed my option c badly. What I meant was what you have clarified: paste all the contents of .default-release into (the newly created) .default/.default-release folder (whichever name the new Thunderbird installation on the new laptop has set it up as).

Thank you so much for the link to the 'Profile Manager create & remove Thunderbird profiles' article. This is exactly what I needed & hadn't been able to find. The objective would be to have a personal profile as a default and a "business" profile as a secondary. There is only me using this laptop so I don't need two Windows Users. The "business" profile would be for one or two email accounts which I have in common with another person located elsewhere. The other person who is located elsewhere would be wanting to create a similar situation (two profiles) on their laptop. The two of us put different things into our "business" Local Folders (storage) because the purpose of our stored mail needs are different. In my case I want the two "business" email accounts in both profiles because I store different emails in Local Folders on each profile for different purposes. Currently I use two separate laptops to keep these two profiles separate, but the plan is eventually to amalgamate both onto one laptop. [Hope I've explained clearly]

Unfortunately I have realised I have supplementary questions:

If I want to import simply the Local Folders (with its structure including sub-folders etc) from one Profile to another Profile whilst retaining the original Local Folders contents and structure (so ending up with both lots of Local Folder contents within one profile), how do I do this please ? In this instance I wouldn't want to import the account setup or anything else, just simply copies of the Local Folders contents. (There seems to be some information at the end the 'Profile Manager create & remove Thunderbird profiles' article BUT it links to how to do this for Firefox rather than Thunderbird. I want this information for Thunderbird only). Can I perhaps import the Storage Folders.sbd using Import/Export Tools NG or would that overwrite the existing Storage Folders ?

Is .sbd storing the individual emails in .eml format ? If not what format is it storing in & can I store in .eml format instead ?

Where are individual (.eml) copies of each Thunderbird email stored & viewable on the laptop C drive in the same way that one can find & read each individual Windows Live Mail email in C:\Users\<username>\AppData\Local\Microsoft\Windows Live Mai\Storage Folders\<email account ID\Local Folders\<folder name> </p>

Thank you for all your help which is very much appreciated

If I want to import simply the Local Folders (with its structure including sub-folders etc) from one Profile to another Profile whilst retaining the original Local Folders contents and structure (so ending up with both lots of Local Folder contents within one profile), how do I do this please ?

Yes, this can be done. For illustration purposes, let's assume the following:

Local Folders to be imported = LF2 Source profile folder where LF2 originally resides = PF2 Original Local Folders to be retained as is = LF1 Target profile folder where LF2 lot will reside in after importing = PF1

This is how I would go about it:

1. Launch Thunderbird using the target profile into which you want to import LF2 lot.
2. Under the Local Folders account, create a new folder and name it Imported. This will be the new home of the imported LF2 lot.
3. Create a sub-folder under the Imported folder, and name it Temp.
4. Open the target profile folder ,PF1, then Quit/Exit Thunderbird.
5. In PF1, go to the Mail > Local Folders directory. Inside you will find a folder named Imported.sbd
6. Open the source profile folder, PF2, in a new File Explorer window, and go to the Mail > Local Folders (LF2) directory.
7. Select everything inside LF2 and copy them.
8. Paste them into the Imported.sbd folder that is open in the other File Explorer window.
9. Launch Thunderbird. Under the Local Folders account, you should see everything that LF2 contained, under the Imported folder.

Where are individual (.eml) copies of each Thunderbird email stored & viewable on the laptop C drive in the same way that one can find & read each individual Windows Live Mail email

Thunderbird does not store messages as individual files on disk by default. It uses a single mbox file for each folder in Thunderbird. These mbox files do not have any extensions. For example, the Inbox folder in Thunderbird, is actually saved on disk as a single mbox file named "Inbox". Likewise, when you create a folder in Thunderbird, an mbox file of the same name is created on disk. The messages you save in that folder in Thunderbird, are all stored in that mbox file.

See Maildir in Thunderbird

Thank you for your explanations in your last two replies.

After a lot of thinking through I got the hang of answer one. I will try & store the answer describing the method safely until I need to employ it.

I found the answer to what I wanted to achieve in relation to the question you have responded to in your second reply. Someone else who clearly had the same goal in mind had worked out the answer for him/herself. See answer 909991. As that poster said "My purpose is to save a plain english record of these emails in case I need a quick printout or read." It is simply a question of exporting the relevant Local Folder(s) in eml format.

Thank you again for all your help