Signed on to Thunderbird a couple of days ago to see a message about a new release. Seeing no way around it, I went for the update. Thunderbird now opens to a screen asking for an account setup.

This is typical for a corrupt prefs.js file in the Thunderbird profile. This often happens after a PC or Thunderbird crash or after a power interruption. When it happens Thunderbird renames the damaged prefs.js file to prefs-x.js (or invalidprefs.js) and creates a new virgin prefs.js file which doesn't contain any account settings. So Thunderbird on startup prompts the user to setup an account with an existing email.

If you have a recent backup of your TB profile folder copy the prefs.js file and - Thunderbird closed - paste it in your actual profile folder. Then restart TB. If there is no backup of the profile folder you must re-create all your accounts. If yours are POP accounts you must link each newly created account with its original "pop.xxx.xx" account folder in the Mail folder of your profile. To do this go to Account settings > account name > Server-Settings > Message Storage > local folder ... click on "Browse" button, navigate to the original correspondent "pop.xxx.xx" account folder in Mail, select it and click "Open". TB will ask you to restart and you should see the old folders and messages of this account.

Thank you Mapenzi. I tried your suggestions the best I could with limited technical knowledge, which became apparent when the steps recommended did not always match up with the options on screen. Common experience for me. I have managed to get my calendar back, including the sub-calendars (folders) and other settings, but not content. I can recreate that. Got my address book back in tact. Got all my previous email back, including folders and their content via Import. However, I had to create a new profile and now the challenge is to have that linked properly to the mail server (AOL). Sill working on that.

However, I had to create a new profile and now the challenge is to have that linked properly to the mail server (AOL). Sill working on that.

Did you have POP or IMAP accounts before executing the incriminated Thunderbird update? Can you still verify in your previous profile folder whether it contains a rather big prefs-1.js file next to a prefs.js file with a size of 6 or 7 kB?

POP pref.js 46kb currently, originally was 7 or so kb

POP pref.js 46kb currently, originally was 7 or so kb

I had asked for you old profile, but this is in your new profile!? A virgin (newly created) prefs.js file has 7 kB. If yours has 46 kB it is because you already have created new accounts.

Bluntly, I don't have a clue about this on a file/code level, just the user concepts. I don't know where to find an old profile, if it even exists anymore. This is the only file I can find with this name. I did not have a backup file. I imported the data in AOL into a new mirrored profile (Thunderbird would not recognize the existing profile that had no data) with data being only what was in AOL at that moment. And, I have added some items to the calendar. What do you mean by new accounts?

Your informations are not clear and you don't reply to some of my questions which I ask to have better informations. You said earlier "I had to create a new profile...." and now you reply "I don't know where to find an old profile, if it even exists anymore. ..." I am very sorry that I cannot help any longer by asking questions and getting only sparse answers. What I am doing actually is trying to solve a puzzle without seeing the puzzle pieces which are hidden in haystack .... Maybe some screen shots with the contents of the folder "Profiles" and the profile folder xxxxxxxxx.default-release (or similar) could help to have an idea what is happening in your Thunderbird installation ....

If I am not answering your questions, it is because I don't understand them.

I am sending some screenshots of the profiles page and the two pages of files in the first file starting with 153xxx....

Maybe this will help.

Thanks for the screen shots. Unfortunately they are too tiny (or have a bad resolution) that even when magnifying them I can't identify most of the folders and files and/or their modification dates. Please make the same screen shots again in a better resolution and when you add them to your answer verify if they are "readable". And also verify whether the folder "Profiles" contains only one profile folder (the one you show in your screen shots) or a second or a third profile folder! Please also show a screen shot of the Folder pane (left part of the main window), you may anonymise the account names (email addresses).

I hope these images are better. There are two profile folders in the larger "Profiles" folder:

153wuk2h.default-esr and fdeclaz3.default

The first two images are from the former (153...) and the remaining four are from the latter (fdec...).

Yesterday, I did not see all the pref.js files in the latter folder. Hope I haven't messed things up too badly.

Thanks for your patience.

Thank for your new (a bit unconventional) screen shots. Now I can see that you have two profiles: • the old one called "default" going back at least to 2015, which worked until August 5, 2025 • a new one called default-esr and created on the same day on August 5, 2025

In the old profile folder I'm seeing a prefs-9.js file from July 9, 2025 which is one month earlier than the latest update. So my initial suspicion that your problem was caused by a corrupt prefs.js file is not confirmed. The creation of a new profile during a Thunderbird update is very rare, I have never seen this on my Mac. I don't know which TB version you used before your update and whether it was a 32bit or a 64bit version. But it is near evidence now that actually you are running a new profile.

I understand that after the update when Thunderbird asked you to "set up your existing email address" you tried to do this but you did not succeed. So actually you are at the same stage without any account and no possibility to receive and to send messages?

Which is the actual page (main window) when Thunderbird opens? Can you post one more screen shot: go to \AppData\Roaming\Thunderbird\ , look for a profiles.ini file, open it in a text editor and take the shot. Maybe this file on your PC has no extension and you will only see a file "profiles" (not the folder "Profiles")

Sorry for the slow response--busy week. You are correct. Basically everything seems to be working except the ability to send and receive messages through the AOL server.

The image attached is the opening page of Thunderbird.

Here is the content of the profiles.ini file in the main Profiles folder:

[Install8216C80C92C4E828] Default=Profiles/153wuk2h.default-esr Locked=1

[Profile1] Name=default-esr IsRelative=1 Path=Profiles/153wuk2h.default-esr

[Profile0] Name=default IsRelative=1 Path=Profiles/fdeclaz3.default Default=1

[General] StartWithLastProfile=1 Version=2

Thanks for sticking with this.

Your Thunderbird main window looks almost normal with some eccentricities: Local Folders as a subfolder of Inbox is not normal but maybe it is not nuisible.

Basically everything seems to be working except the ability to send and receive messages through the AOL server.

Does that mean that you cannot setup the AOL account? Do you get an error message? Not being familiar with US ISP I won't be of great help... Probably I won't be able to reply until this week-end.