I have experienced similar problem today after upgrade to Thunderbird 137 via winget in Windows 10.

• I can see message list and also open and read messages, but only in folders named in ASCII characters.
• Folders with national characters (like "vyučovanie") I can open, I can see message list, but when I open any message, it displays just empty window.
• Message date doesn't matter.
• All my accounts are POP3.

I have found my Thunderbird profile (it is a very large file because I have a lot of old email). App Data - Roaming -Thunderbird - Profiles - alphanumeric file name. How do I get Thunderbird to use the named file I found?

You can manage profiles here:

Help - Troubleshooting information - about:profiles

If the found profile is where you posted, the easiest way is to click the profiles.ini text file in the Thunderbird folder and change the name of the default profile to the name you located. Do that when thunderbird is not running. when you restart thunderbird, it will open that profile.

Thanks All. The mystery deepens. I changed nothing, the profile file name already matched the profiles.ini text file and the installs.ini too. There should have been no problem to fix, right? I can only see about 100 emails and the profile properties reads 621 files, 100 folders 12.3GB which is a whole lot more than one would expect from 100 emails, right?

This may or may not have anything to do with the problem, but: Thunderbird Version 128.9esr (32bit) was installed April 5, 2025 10:21P. The first message I now have on Thunderbird is dated April 6, 2025 2:54P. My phone shows a dozen or more messages between those 2 times.

Any other fixes or ideas? I really want those emails back if possible.

I wonder if switching to the monthly releases and trying version 137 would help.

I know almost nothing about POP accounts, so please don't act on my idea yet, but it may help other support people to know what is in your profile. Would you please access it through the file system (App Data - Roaming -Thunderbird - Profiles - alphanumeric file name), try to find the folder that holds your POP mail, and post a screenshot of its contents with folder names and sizes (hiding anything private and personal)?

I want to confirm that the folders are still in your profile but just not appearing in Thunderbird. That seems to be the case.

Switching releases may just postpone this resolution. I agree that seeing the profile will help.

Here is screenshot of my profile. When I rename mail folder "vyučovanie" to "vyucovanie", messages are displayed correctly, when I rename it back, empty windows again. In my case, problem is non-ASCII character in folder name, but it was working until now. This is not my only not-working folder, I have much more in more levels of hierarchy, the screenshot is just small part with non-private data.

Hi Scooter and David: I have taken the precaution of copying my Profile to an external drive as a backup in case. It is a big file so it took a while. Apparently Thunderbird is working well enough to add a pop.earthlink-1.net to my mail folder. I have added a couple of screen shots that might give you some ideas of what is going on and how I might fix it. If Thunderbird can add a file where it did why can't it read the file that is already there? Is my pop.earthlink.net file just too big with too many folders? Thanks in advance for your help. Bob

Your system seems to be infected with deal4real adware. Maybe that is the problem.

I will see what I can do about removing the deal4real adware. It can't hurt to get rid of that sort of thing. Certainly worth the try.

Do you have more than one earthlink account? Can you show us a screenshot of how the inbox appears in thunderbird? Your screenshot of inbox looks incomplete.

I was being cautious when I said that deal4real may be the problem. Although I am not familiar with it, it seems to me that it is preventing Thunderbird from even recognizing some mbox files. It may have also corrupted the contents of those files.

Everything has been helpful but hasn't solved the problem , YET. I still have emails back to April 6 and have the emails to date as well, which seem to be from pop.earthlink-1.net. Now i have a pop.earthlink-2.net, pop.gmail-1.com, pop.yahoo-1.com and smart mailboxes-1 that I didn't have before. I don't know what is happening. I had thought of renaming pop.earthlink.net to pop.earthlink-1.net and the existing pop.earthlink-1.net to pop.earthlink-a.net and see what happened. With Thunderbird adding pop.earlink-x.net I don't want to try it without some additional input from someone who has more experience than I do. Dave, Scooter, anybody: thoughts, suggestions. I have a back up copy of the Mail file.

Thanks in advance, Bob

Have you disinfected your computer and removed deal4real? I suspect that is what is preventing Thunderbird from showing you your folders.

I do not know why you have duplicate accounts.

Are you running anti-virus software?

You might check to see if you have more than one prefs.js file in the profile's root folder. When folders are created with same name and a number, it often means that thunderbird's attempt to update the prefs file is failing.

I have removed deal4real (4 copies!) with my anti malware tool. Here are a couple of more screen shots there is some change in the file type. I cannot find the perfs.js file(s). I have looked around a lot in the profile folder. I have the profile folder saved to another hard drive. Do I need to get drastic and reinstall Thunderbird and copy the profile folder back and replace the name(s) with the one from the new install?

I really appreciate your efforts Bob

it's prefs, not perfs - and reinstalling accomplishes nothing good.

File types are still deal4real. :(

Thanks for all the help, David and Scooter. I have saved the profile with pop.earthlink.net on a separate hard drive so it is safe and Thunderbird is usable for now getting and saving my daily email to the pop.earthlink-1.net file in the Mail folder. For now I am not going to pursue further getting all my old email back on Thunderbird. It is safe even though I can't get to it right now. When life slows down a bit I plan on looking for a program that can extract the messages and attachments. If you have any suggested programs to do that mission please let me know. Otherwise, thank you for your help. I hope this thread can help others.