It seems to happen with pop protocol and not with imap. Started to appear today .

Interesting! Turns out 3 of my 4 accounts have been set up as POP. The fourth is my gmail which is IMAP and I realize it's working just fine after testing it. I'm not sure I can change the others since the server, Sympatico, is POP.

I have this exact same problem. Started today. We're also using sympatico.ca as our ISP and POP as the protocol. My wife is in the same situation. It appears we have the good fortune to be among the first afflicted.

I have this exact same problem. Started today. We're also using sympatico.ca as our ISP and POP as the protocol. My wife is in the same situation. It appears we have the good fortune to be among the first afflicted.

Thunderbird 141 has been out for some weeks. So if none if you had immediately updated Thunderbird before the problem started, then the problem would seem to be caused by sympatico ?

No, I use different email providers (orange, ovh...). It's not a sympatico issue.

I should have been more explicit - please also respond regarding "had you immediately updated Thunderbird before the problem started?"

I should have been more explicit - please also respond regarding "had you immediately updated Thunderbird before the problem started?"

No, it should had been automatic update, I guess.

> No, it should had been automatic update, I guess.

I'll take that to mean there was no update of any type just before it stopped working.

But in case I'm not being clear, my question is - had Thunderbird been updated (manual or automatic - doesn't matter) between when it had been last working and when it first stopped working? The date+time update history can been seen at Help > Troubleshooting Information > show update history.

But in case I'm not being clear, my question is - had Thunderbird been updated (manual or automatic - doesn't matter) between when it had been last working and when it first stopped working? The date+time update history can been seen at Help > Troubleshooting Information > show update history.

The history says update 140.1.1esr was installed on 08/08. But the version running is 141.0, not in history. But as I tried to reinstall T-bird with latest version and backup profile today, maybe it's normal not to see the latest update?. Also, latest version fresh installed on other computer shows same problem.

For me, the history shows Ver 140.1 was last auto updated Aug 7 and only today did it stop receiving emails correctly. Earlier today I reinstalled Thunderbird hoping that might solve the problem. Now it's Ver 141.0 which is still having the same POP issue.

I downloaded emails last night at 10PM and everything was fine. This morning - first thing this morning (9AM) - the problem was there. I certainly didn't update anything during the night. According to other replies the problem is seen across multiple ISP servers. Was there some change the in overall POP environment that might have triggered this?

>I downloaded emails last night at 10PM and everything was fine. This morning - first thing this morning (9AM) - the problem was there.

Timing for this starting for me seems to be identical to Barry54. What can we do to have this looked into by Mozilla? Driving me crazy trying to read emails like this!

Installing a download from https://thunderbird.net/download/ will get you release channel version 141 (unless you changed the channel setting on that page), which will install over esr channel version 140 and will not show up in the update history.

If an install or update happened immediately prior to problems, there are at least two possible causes for the problem: 1) Thunderbird, 2) some networking problem which can happen from software such as VPN, proxy, antivirus.

I have this exact same problem. Started today. We're also using sympatico.ca as our ISP and POP as the protocol. My wife is in the same situation. It appears we have the good fortune to be among the first afflicted.

Barry's original posting at https://support.mozilla.org/en-US/questions/1528610

Same problem here, on both my PC and my wife's. Started morning of 8/11/2025. ISP is Optimum / Optonline.net using POP. Thunderbird version 140.1.1esr (32-bit).

Installing a download from https://thunderbird.net/download/ will get you release channel version 141 (unless you changed the channel setting on that page), which will install over esr channel version 140 and will not show up in the update history. If an install or update happened immediately prior to problems, there are at least two possible causes for the problem: 1) Thunderbird, 2) some networking problem which can happen from software such as VPN, proxy, antivirus.

Two of us have already confirmed that there was neither an update or install just prior to the problem occuring. The issue must be with TB since I'm getting emails perfectly on my phone. I much prefer dealing with email on my desktop with TB, though.

Try to unistall and reinstall BitDefender Total security if you use it. It worked for me.

Hi Since yesterday afternoon, I have noticed a problem identical to the one reported above

• on the only POP account among 6 IMAP accounts,

   * the subject is not displayed
   * the display corresponds to the text source of the message (in other words, unusable).

• Thunderbird version is 140.1.1esr
• The latest update is: 'Since yesterday afternoon, I have noticed a problem identical to the one reported above
• on the only POP account among 6 IMAP accounts,
• the subject is not displayed
• the display corresponds to the text source of the message (in other words, unusable).
• The Thunderbird version is 140.1.1esr
• The latest update is: 'Les mises à jour suivantes ont été installées

Thunderbird 140.1.1esr (20250805025534) Installée le : 9 août 2025 à 16:27:09 État : La mise à jour a été correctement installée. Détails...' In English : ‘The following updates have been installed. Thunderbird 140.1.1esr (20250805025534) Installed on: 9 August 2025 at 16:27:09 Status: The update was installed successfully’.

Try to unistall and reinstall BitDefender Total security if you use it. It worked for me.

Well, at least it worked a few minutes. Problem is back, but it is still a Bitdefender concern. Reinstall solves the problem again. I'm trying now with immediatly disabling the Antispam option and Bitdefender extension in T-Bird see if it lasts.

Same problem here. I am using Windows 10, Thunderbird 142.0b3, Bitdefender Total Security. I have tried disabling Bitdefender Antispam, to no benefit.

I notice that when I view message source the message headers there is a blank line in the headers. If I save the message, edit out the blank line, and open the edited message in Thunderbird, then the email is parsed correctly. It seems to me that thunderbird is interpreting the blank line in the message header as the start of the message content and displaying it as is, without interpreting subsequent header info or HTML. This results is a mass of code presented in the displayed message.

I am unable to determine where the blank line is originating, whether that be in Bitdefender or Vade or whatever. I would have thought it feasible for Thunderbird to ignore blank lines in the headers until maybe a Subject line is reached.

NB. I can successfully read these emails on my ISP website.