Public bug reported: This seems similar to https://bugs.launchpad.net/ubuntu/+source/xubuntu- default-settings/+bug/1754888
4 files affected: /usr/share/applications/org.kde.mobile.okular_chm.desktop, /usr/share/applications/org.kde.mobile.okular_djvu.desktop, /usr/share/applications/org.kde.mobile.okular_epub.desktop, /usr/share/applications/org.kde.mobile.okular_tiff.desktop The message is <Unknown error. Desktop file appears to be valid.> There are Okular desktop files for these mimetypes that work, e.g. /usr/share/applications/okularApplication_chm.desktop Both broken and working files have the same timestamp. The broken files e.g. start with <MimeType=image/tiff; Name=Reader>, but the working files start with <MimeType=image/tiff; Terminal=false Name=Okular> The broken files have the line <InitialPreference=1>, the broken <InitialPreference=2> ** Affects: okular (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1859647 Title: Invalid desktop files in XUbuntu 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/okular/+bug/1859647/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs