What's your version of Owl? 0.7.7.2 arrived today. If it's only happening with the Owl account, it's best to contact the author directly.

@sfhowes That is a wonderful suggestion. Thank you. I checked and my Thunderbird says that my Owl for Exchange add-on was last updated today, to version 0.7.7.2; thus, this does seem to be a logical connection for why I am seeing this issue just today. I have now sent an email to the add-on author and will wait for a reply (fingers crossed). Hopefully, this will be the culprit and be able to be fixed; otherwise, it will be back to the drawing board. I will post here any follow-ups.

Also see https://support.mozilla.org/en-US/questions/1322371

Hi, I have exactly the same problem since yesterday afternoon. I am happy to see that I am not the only one! I already contacted the developer of the Owl add-on. Please do so as well if you have the same issue. owl.support@beonex.com

@christ1 Thank you. That post started within 24 hours of this one. At least others are having the same issue, which gives credence to the idea that this is not just me doing something funny on my end. I am sorry to hear that you are having the same issue though :(

I just realized that my Thunderbird is not rebuilding my .msf profile for this one email account, which is likely related to this problem. I tried deleting my .msf profile for this one email account and restarting Thunderbird so that Thunderbird would rebuild it and hopefully correct this issue. Well, it never does rebuild it. It is actually missing in my profile folder. I can still send/receive emails and see things though (with the same problem of messages disappearing every time it checks for new messages). Anyway, more information to chew on.

Owl updates have been issued in a flurry (now 0.7.7.4), so it might be worth waiting until it stabilizes(?) before trying other steps to remedy the problem.

@sfhowes Thanks! I updated (to 0.7.74) and was optimistic, but no luck yet - same problem.

Make sure to restart Thunderbird after updating the add-on.

@christ1 I did, but alas, no luck :(

@applejack: Can you try to restart your Mac, and see whether that fixes it? (I normally don't ask people to do restart the computer, only Thunderbird, but in this case, the bug was that we opened too many files at the same time. Another Mac user also said that he continued to have problems.)

We're sincerely sorry for the problems.

If the problem continues even with Owl 0.7.7.4, and even after a restart of your computer, please try create a new Thunderbird profile, install Owl, and try to set up the account there. If it still doesn't work, please write to owl.support@beonex.com with a copy of your error console (Thunderbird menu | Tools | Developer | Error Console, and copy the entire contents as text), please. The more you can tell us about the problem, and what you do when it appears and even in which cases it works, the easier it will be to find the problem. We've been working overtime in the last few days to find the root cause and fix it.

Again, we're really sorry for the problems we've caused you.

I have the same problems, update to 0.7.7.4 and messages still disappear. There is nothing in the dev console when they disappear.

I've had this in the dev console:

TypeError: prin.URI is null ConduitsParent.jsm:123:58

Error: Unknown sender or wrong actor for recvCreateProxyContext ConduitsParent.jsm:321:13

Edit: seems unrelated, as message disappear from the panel even without these errors showing up.

Problem solved for me on Win 10 enterprise by a silent automatic update. Thanks for the excellent support from Owl people!

It seems the disappearing messages only occurs in sub-folders.

I dezipped the owl source and I see you commented-out fetching sub-folders in the "hotfix", so it is normal the content disappear?

EDIT: Moving the sub-folders to be top folders does not fix the problem. But it seems to occur less frequently, but it may be just an impression.

@Owl Problem persists with Owl 0.7.7.4. Restarting Thunderbird does not work. Restarting my Mac does not remedy the problem. Creating a new Thunderbird Profile does not work. I will write to owl.support directly with a copy of my error console.

For everyone: The problem has lessened some. The disappearing still occurs but in more limited cases now. Before, any message (in any sub/folder) would disappear every time Thunderbird checked for new messages. Now, only messages in my Inbox and subfolders disappear when Thunderbird checks for new messages but only for one cycle after these two cases: (1) I receive a new message, or (2) I view a new message.

For example, things appear fine and messages remain until I receive a new message, then once Thunderbird checks for new messages again, my messages disappear. I bring them back and they stay, even when Thunderbird checks for new messages again. As long as I receive no new messages (or view no new messages), then my messages remain.

Owl v0.7.7.5 has fixed it for me.

Owl v0.7.7.5 has fixed it for me, too :)

Just for completeness and fairness to Owl Support, they did respond to me through email and were sincerely sorry and helpful. They have been working really hard to get this fix out there for folks.

For anyone else where Owl v0.7.7.5 did not fix your issue, please try their following suggestions:

• update to latest version of Owl (currently, version 0.7.7.5) and restart Thunderbird
• If the problem continues, try to restart your computer
• If it still continues, create a new Thunderbird profile, install Owl, and try to set up the account there
• If none of that works, please write to owl.support@beonex.com with a copy of your error console (Thunderbird menu | Tools | Developer | Error Console, and copy the entire contents as text)

Thanks everyone!

Hey applejack,

Yes, we are truly sorry for the problems we caused you. Thank you for your understanding. We've had a stressful few days, while trying to fix it.

I'm happy that 0.7.7.5 fixed it for you and everybody else so far.

Sorry again.

Ben Bucksch CEO