This is very disturbing. I loaded up Kontact this morning to check my email. I noticed that it seemed to be more active than usual. I have around 15 email accounts, all IMAP. While reading the emails in one of my Gmail accounts, two emails disappeared right before my eyes. These emails were something I actually wanted to read. I checked the trash to see if I had accidentally deleted them. They are not in the trash.

After some time, I figured out what was going on. In the status bar to the left it showed a message that a large number of emails were waiting to be filtered. I clicked for status details on the right and a lot of messages like this were scrolling by:

Downloading message data...
Uploading Message data...
Moving messages...

I have no idea where the messages were moved to, because the status didn't give any details. I didn't accidentally apply any filters. To do so requires a right click then navigating to a submenu and selecting the filter to be applied, after selecting all the messages in the account.

I do have the Bogo spam filter activated, but I'm not sure why it would suddenly decide to run like this on a single email account and delete important emails. Luckily this is a Gmail account and I didn't activate permanently deleting emails, so I can still access the emails in the All mail folder online. I checked the Spam folder for Gmail online and the messages are not in there.

It is very scary that Kmail is suddenly running a filter on an entire email account, uploading, and moving messages to some unknown location. If this had happened on one of my regular, important IMAP accounts, it would be a disaster.

Any ideas what happened and how I can figure out where the messages were moved to?

This is very odd behaviour. I have once before seen a similar report, but don't recall whether the cause was ever found.

If it were me, I'd de-activate bogofilter while testing, although I have no reason to suspect that it's involved - it just rules out one source of the problem.

Similarly, I'd copy out any other filters I have installed, then remove them.

Then I'd do a search on my whole home directory looking for an mbox file. If something has tried to move them but couldn't locate the directory that it's expecting, there's a fair chance that it has filtered them into an mbox file, in which case they will still exist. If you find it - check by reading in a text editor - you can create a temporary file under your local inbox, mbox type, and then move the whole file there. The messages should then show up in your new folder, and you should be able to move them to their correct place.

If all that works you've got good reason to suspect a filter, either your own or bogofilter's. Replace your own first, one at a time. If everything is still OK you have to suspect bogofilter. At that point you have two choices - reactivate bogofilter and see whether it happens again, or send your bogofilter settings to the bogofilter mailing list (http://www.bogofilter.org/mailman/listinfo/bogofilter) and ask for them checking. It's a low-volume list and they are helpful.

Unfortunately I can't check them for you as I use bogofilter within procmail, which is rather different.

Thank you for the quick response.

I went through every single filter, and made sure that they are only running on the appropriate account and that there isn't anything screwy. I didn't see any problems in the filters that are created, either ones that I created or the ones created by Bogofilter.

I decided to close Kontact and open it up again to see what happens.

HELLLLLP!

It is doing it again. "568 messages waiting to be filtered. I quickly opened the status arrow on the right, and it appears to be running on the same email account again. Then I shut Kontact down to prevent it from running further. The program crashed (actually, Kontact seems to crash rather frequently, there are definitely some stability issues with Kontact in Kubuntu 9.10).

Anyhow, I'm somewhat glad this issue came back. Now that it is back, is there anything I can do next time I open Kontact to figure out where the messages are being moved to? Hopefully, there is some way to recover the messages that were mistakenly moved so that I don't have to filter through the 3500+ emails in the Gmail All folder to retrieve the ones I wanted to have saved.

For now, I'll be checking my email in Thunderbird on my other laptop.

I would suggest that you, at least temporarily, sign up for the kdepim-users list, at https://mail.kde.org/mailman/listinfo/kde-pim . One of the development team reads the list most days, and if he doesn't know the answer he's in the perfect position to ask the right questions of someone who should know. I can't even say it's a kubuntu problem, although I think the other person who experienced it also used kubuntu. Still, if you join the list, Ingo Kloecker is the expert to listen to - whatever anyone else says (including me) his advice is the one to heed.