On Mon, Oct 21, 2019 at 20:33:35 +0100, Chris Green wrote: > I removed the apparmor package, and I stopped it using systemd, and I > rebooted the machine. I still have the error with evince, so I'm > pretty convinced it's not to do with apparmor.
I agree that you'd think rebooting the machine after purging the apparmor package would be enough to disable Apparmor enforcement... but looking at the version number of the Apparmor package for Disco shown in https://packages.ubuntu.com/search?keywords=apparmor (i.e. 2.13.2-9ubuntu6) and then the change history for Apparmor upstream: https://gitlab.com/apparmor/apparmor/commits/v2.13.2 ... it really looks like the "deny ~/.mutt** in private-files" change is indeed included in the version found in Disco. So, while it could be that something else is going on as well, it seems very likely that Apparmor is at least part of the reason you have been getting errors when trying to use ~/.mutt for temporary files on Disco.... and thus probably worth further investigation (especially since so far no one has proposed any alternative explanations...) It looks like even with the apparmor package purged you could run $ sudo cat /sys/kernel/security/apparmor/profiles to see if in fact Apparmor profiles are still loaded. Also, assuming still have apparmor installed on the other Disco system where you were seeing this problem, you could also try installing the apparmor-utils package there (if necessary) and then run something like $ sudo aa-complain /usr/bin/evince to set the mode for that profile to complain-only, and see if that that makes any difference in the Evince's behavior. Nathan