Also I'm pretty sure the bug lies in the package shared-mime-info. It certainly isn't limited to Nautilus alone since I use Kubuntu and the bug shows up there:
Processing triggers for shared-mime-info (1.2-0ubuntu3) ... Unknown media type in type 'all/all' Unknown media type in type 'all/allfiles' Unknown media type in type 'uri/mms' Unknown media type in type 'uri/mmst' Unknown media type in type 'uri/mmsu' Unknown media type in type 'uri/pnm' Unknown media type in type 'uri/rtspt' Unknown media type in type 'uri/rtspu' -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to shared-mime-info in Ubuntu. https://bugs.launchpad.net/bugs/193325 Title: "unknown media type" during update Status in Nautilus: Confirmed Status in shared MIME database: Fix Released Status in shared-mime-info package in Ubuntu: Fix Released Bug description: Messages below seen during the latest round of updates. The messages from several packages seem to be mixed around, so I'm not sure which one triggered them. I suspect nautilus. Setting up shared-mime-info (0.23-3) ... Unknown media type in type 'x-content/video-vcd' Unknown media type in type 'x-content/video-svcd' Unknown media type in type 'x-content/video-dvd' Unknown media type in type 'x-content/image-dcf' Unknown media type in type 'x-content/audio-cdda' Unknown media type in type 'x-content/blank-cd' Unknown media type in type 'x-content/blank-dvd' Unknown media type in type 'x-content/blank-bd' Unknown media type in type 'x-content/blank-hddvd' Unknown media type in type 'x-content/audio-dvd' Unknown media type in type 'x-content/video-bluray' Unknown media type in type 'x-content/video-hddvd' Unknown media type in type 'x-content/image-picturecd' Unknown media type in type 'x-content/audio-player' Unknown media type in type 'x-content/software' Setting up ucf (3.004-0ubuntu3) ... Setting up seahorse (2.21.91-0ubuntu3) ... Unknown media type in type 'x-content/video-vcd' Unknown media type in type 'x-content/video-svcd' Unknown media type in type 'x-content/video-dvd' Unknown media type in type 'x-content/image-dcf' Unknown media type in type 'x-content/audio-cdda' Unknown media type in type 'x-content/blank-cd' Unknown media type in type 'x-content/blank-dvd' Unknown media type in type 'x-content/blank-bd' Unknown media type in type 'x-content/blank-hddvd' Unknown media type in type 'x-content/audio-dvd' Unknown media type in type 'x-content/video-bluray' Unknown media type in type 'x-content/video-hddvd' Unknown media type in type 'x-content/image-picturecd' Unknown media type in type 'x-content/audio-player' Unknown media type in type 'x-content/software' Setting up ubuntu-gdm-themes (0.24) ... Setting up linux-restricted-modules-common (2.6.24.9-8.25) ... Setting up nautilus-data (1:2.21.91-0ubuntu3) ... Unknown media type in type 'x-content/video-vcd' Unknown media type in type 'x-content/video-svcd' Unknown media type in type 'x-content/video-dvd' Unknown media type in type 'x-content/image-dcf' Unknown media type in type 'x-content/audio-cdda' Unknown media type in type 'x-content/blank-cd' Unknown media type in type 'x-content/blank-dvd' Unknown media type in type 'x-content/blank-bd' Unknown media type in type 'x-content/blank-hddvd' Unknown media type in type 'x-content/audio-dvd' Unknown media type in type 'x-content/video-bluray' Unknown media type in type 'x-content/video-hddvd' Unknown media type in type 'x-content/image-picturecd' Unknown media type in type 'x-content/audio-player' Unknown media type in type 'x-content/software' Setting up compiz-core (1:0.7.0-0ubuntu3) ... To manage notifications about this bug go to: https://bugs.launchpad.net/nautilus/+bug/193325/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

