LastVersion= line in compatability.ini file in the profile directory has version information.

Did you erase your data or just re-install macOS?

Thanks for the pointer to the profile compatibility data.

My user data is on an internal storage device, separate from the system device. I did erase the system drive (at the request of the Apple Support line, so that I could install a clean, latest version, macOS before they passed my macOS problem up the support hierarchy to get help). So I had to reinstall Thunderbird. It does not like the profiles.

In 2023, I was using 102. When 115 was released, I installed it. It did not work for me, and I downgraded to 102. After the 2025 clean macOS install last week, I installed the currently offered release. It worked fine in my admin account, with a newly configured e-mail server account.

But, it did not like the profiles in my two user accounts.

Looking at the compatability.ini files, I see one profile says 115.10.1 and the other 115.18.0. I installed 115.10.1 and the first profile is accepted, but not the second. I'll look for instructions on upgrading from one 115 to another. Once I have the second account working, I'll upgrade to 128, then 139; a step at a time.

Since late last year, while struggling with macOS, I had been using the two profiles on the second device, from the admin account on the system device. Now, after the clean OS install, I am working my way back toward normal.

Hi Joaquin,

Erasing the system volume should not affect applications installed on the data volume or another user-controlled volume, so I am curious about why you had to re-install Thunderbird. Where in the file system are you installing Thunderbird?

Do you actually have two internal storage devices (do you have a Mac Pro?) or do you mean two volumes on one storage device?

In your first post, you were seeking answers that would help you solve a problem that you did not define. People here may be able to help you more if they understand the problem itself better. So ...

What do you mean that Thunderbird does not like your profiles? How are you connecting Thunderbird to your profiles? What happens when you do?

In what way did version 115 not work for you? From which computer accounts? Accessing profiles stored where?

What do you mean when you say that a profile is "accepted" and not accepted? Which profiles by which computer accounts? How are you trying to use the profiles? What happens when you do?

You refer to an admin account and two user accounts. Are you trying to get Thunderbird in each account working with two or three profiles? Now my first question is more relevant: Where is the Thunderbird app? Where are your profiles? Are they all in ~/Library/Application Suppport/Thunderbird/Profiles?

If the profiles are in the default location in ~/Library/Application Suppport/Thunderbird/Profiles, then the admin account can access all profiles and the non-admin accounts can access only their own profiles. Putting the profiles outside the permissions of the non-admin accounts would explain why Thunderbird works with all profiles from the admin account but not from the non-admin accounts.

But why multiple accounts and multiple profiles and the desire to access two or more profiles from one account? Do you need this complexity?

I suspect that the version of Thunderbird is not important here. Your app and profile organization may be important.

But I am making guesses about the problem, so this line of inquiry may not be helpful. Would you please tell us more about the problem itself?

Thanks. I will tell you more. I have a full day today; tomorrow I will have time to prepare answers to your questions.

Two quick answers, which should help: > I have never installed applications in a user's Library. I have two user accounts, one for work and one for everything else. I install all applications in /Applications. So all applications were erased and only those that come on the OS file were installed after the erase. (I did not restore the system device from my backups, because Apple wants a clean install to pursue my bug-or-design-flaw.) > I have several storage devices (yes, Mac Pro). The user data is on a separate "Internal"* storage device, not on the system device. The two profiles are in /Volumes/User Data/<user>/Library/Thunderbird. User Data is a volume on a separate device. One profile in each user directory.

Well, three: > I erased only the system device, /. I did not not erase the user data device. After the erase, I confirmed that the OS problem was still present. I then installed Thunderbird on the system device.

 *  As I expect you know well, macOS has four kinds of storage devices: System, SATA, bus and truly external. System and SATA are classified as "Internal" and both internal storage on the bus and truly external devices are classified as "External."

Thanks, Scooter. Here are the answers to your questions.

Where in the file system are you installing Thunderbird? > On the system storage device, at /Applications

   See my previous response for more on this.

Do you actually have two internal storage devices (do you have a Mac Pro?) or do you mean two volumes on one storage device? > Two internal devices; Mac Pro.

    See my previous response for more on this.

What do you mean that Thunderbird does not like your profiles? > Says the profile is missing or damaged.

How are you connecting Thunderbird to your profiles? > I start Thunderbird and the profile manager opens. The most recent profile is highlighted. I click to open.

  (While struggling with macOS since October, I at first could not open the user accounts, I copied the profiles from the two user accounts to /Users/Administrator/Library/Thunderbird, and used e-mail from there.  Since I had two separate user profiles, I was using the profile manager. After the reinstall of macOS, see the answers below.)

What happens when you do? > Thunderbird will not open the profile. See the previous answer.

In what way did version 115 not work for you? > Would not open the profile. From which computer accounts? > Both macOS user accounts. I created an third e-mail account for Administrator on the e-mail server. Thunderbird, launched from the Admin account, works as designed for that new account. Accessing profiles stored where? > For each of the <now three> users, on ~/Library/Thunderbird/Profiles. (Where ~ is either in /Users or in /Volumes/User Data/Users.)

What do you mean when you say that a profile is "accepted" and not accepted? > Thunderbird will open the profile and work as usual and Thunderbird will not open the profile. Which profiles by which computer accounts? > Each user profile, by the user account which has that profile in ~/Library/Thunderbird/Profiles How are you trying to use the profiles? > Open, receive mail, create messages, send them. What happens when you do? > Works normally with the new Administrator account; with the other two accounts, can’t open the profile.

You refer to an admin account and two user accounts. Are you trying to get Thunderbird in each account working with two or three profiles? > After the October macOS disaster, and before the clean macOS reinstall, I sometimes copied a profile (see above) or made a copy of a profile, and then started using the copy. After that OS reinstall, I used what had been the most recent profile, for each account, in that accounts Profiles folder.

Now my first question is more relevant: Where is the Thunderbird app? 

> /Applications Where are your profiles? > /Volumes/User Data/<User>/Library/Thunderbird/Profiles, where they have been for years. Except for the just created Admin user. Are they all in ~/Library/Application Support/Thunderbird/Profiles? > None. Well, I don’t know where the new Admin profile is, but Thunderbird is quite happy with it. It is wherever Thunderbird created it.

If the profiles are in the default location in ~/Library/Application Support/Thunderbird/Profiles, then the admin account can access all profiles and the non-admin accounts can access only their own profiles. Putting the profiles outside the permissions of the non-admin accounts would explain why Thunderbird works with all profiles from the admin account but not from the non-admin accounts. > During the time I could not log in to the user accounts, they were both in /Users/Administrator/Library/Thunderbird/Profiles. They worked fine there. Since I was again able to log in to the user accounts, the user profiles are back in /Volumes/User Data/Users/<User>/Library/Thunderbird/Profiles.

But why multiple accounts and multiple profiles and the desire to access two or more profiles from one account? > One macOS account for each user.

   The only present reason to access more than one profile from any user account will be to recover any messages that may be in a copied-and-saved profile but have been lost in a later profile for that user.  That is something I will look into after all this is behind me.
   I use Profile Manager only since the time that I could use only the macOS Admin account. Since I am again able to log in to the user accounts, I use Profile Manager in those accounts, but always select the highlighted current profile.

Do you need this complexity? > I need the complexity of having two profiles, one for the user account for my confidential work, and the other for the user account for all else. I doubt I will ever use the third profile for the Administrator account, unless I get into an even deeper macOS problem in the future.

Would you please tell us more about the problem itself? Simply that Thunderbird, opened from /Applications, and asked to use a profile in /Volumes/User Data/Users/<User>/Library/Thunderbird/Profiles, declines to use that profile. Though it was using it for months before the very recent erase and reinstall.

I hope all is covered in my answers above. You’ve seen my post of June 1st.

I now have some time to work on this, and will look at the permissions of the user data, after the macOS erase and "clean" install, the re-creation of the two macOS user accounts, and the configuration of those two accounts to use the user data on the UserData internal SATA SSD, /Volumes/User Data/.

   (Except for Thunderbird, so far no trouble with the few other applications that I have reinstalled on /Applications, including Firefox, which is using my pre-disaster and pre-erase configurations.)

Folks: I apologize for the formatting of the above. Clearly I am not aware of the formatting conventions here.* I did not intend the typewriter font, nor the lack of new lines. Kindly read all that post as simply all plain text.

(Ha!) * Well, having typed that I have a dim memory of years ago having this problem on Bugzilla. If I recall, starting a line with blanks--or something like that--is for certain kinds of text from elsewhere. Those years ago were when a bunch of us were trying to get the Thunderbird volunteers to enable searching of the body of encrypted messages. (We were all preaching the following doctrine of the encryption community: . . Encryption in transit and encryption at rest are two quite different requirements and require separate solutions.

We had no luck.

Joaquin, many thanks for sharing all that information. I'm sorry that I made you work that hard.

In short, you have two macOS user accounts (let's ignore the admin account for now) that use Thunderbird and need to access profiles in a certain location, from which they have accessed those profiles in the past, but when you try to open those profiles from those accounts, Thunderbird does not open them because, it says, they are missing or damaged (or does it say "inaccessible"?). All you want to achieve is using those profiles with those accounts. That is why you asked initially about identifying the version of Thunderbird that those accounts last used: you wanted to fix any incompatibility between the Thunderbird version and the profiles.

Is all that correct?

If so, was the information in the compatibility.ini files helpful? Have you matched the Thunderbird version with the profiles? What was the result?

Can you confirm that the profiles are where Thunderbird expects them to be?

(By the way, I cited the wrong path for the default location of profiles, as I think you know. It is ~/Library/Thunderbird/Profiles.)