I grepped around my Thunderbird folder to see where that inexplicable junk is coming from and found the following.
rgrep -li mbox.*archive ~/.mozilla-thunderbird/ is the command I used. After that I looked more closely at three files. ~/.mozilla-thunderbird/ha2ri4eg.default/ImapMail/192.168.1.10.msf ~/.mozilla-thunderbird/ha2ri4eg.default/panacea.dat ~/.mozilla-thunderbird/ha2ri4eg.default/folderTree.json quoting some lines from ~/.mozilla- thunderbird/ha2ri4eg.default/ImapMail/192.168.1.10.msf <(80=1)(8B=#mbox/Sent)(8D=8082014)(94=21788)> {1:^9F {(k^A0:c)(s=9)} [1(^AC=1)(^AF^8B)(^88^8D)(^B0=1)(^A7^8B)(^B3^94)]} ... <(97=#mbox/Sent/#mbox^Sent^Archives)> [-1:^9F(^AC=1)(^AF^97)(^88^8D)(^B0=1)(^A7^97)(^B3^96)] @$$}B}@ quoting from ~/.mozilla-thunderbird/ha2ri4eg.default/panacea.dat (539D=#mbox)(406 =/home/XXX/.thunderbird/ha2ri4eg.default/ImapMail/imap.arcor.de) ... =/home/XXX/.thunderbird/ha2ri4eg.default/ImapMail/192.168.1.10/75ddfa\ bc.sbd/Archives.msf)(71E09=#mbox/Archives)(74148 ~/.mozilla-thunderbird/ha2ri4eg.default/folderTree.json contained among others (on a single line): "imap://rolf@192.168.1.10/#mbox" "imap://rolf@192.168.1.10/#mbox/Sent" "imap://rolf@192.168.1.10/Trash/#mbox/Sent" "imap://rolf@192.168.1.10/#mbox/Sent/#mbox^Sent^Archives" -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to thunderbird in Ubuntu. https://bugs.launchpad.net/bugs/1289202 Title: archive function does not always work - regression Status in thunderbird package in Ubuntu: New Bug description: == Regression details == Discovered in version: 1:24.3.0+build2-0ubuntu0.12.04.1 Last known good version: 1:24.2.0+build1-0ubuntu0.12.04.1 I am running an up-to-date precise installation. Since about two weeks, pressing 'a' or choosing "Archive" from the context menu stops to work about 50% of the times. I have run thunderbird in safe-mode and it still occurs. This used to work for a long time, so it's a regression. /var/log/dpkg.log.1:2014-02-22 07:53:19 upgrade thunderbird 1:24.2.0+build1-0ubuntu0.12.04.1 1:24.3.0+build2-0ubuntu0.12.04.1 I found above line in the logs so I suspect that's what brought about the regression. I'll try to downgrade for confirmation. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/1289202/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp