I am using Ubuntu 16.04 and recently noticed that Dash home is empty with a message that no applications could be found. This has happened over the last few days and is not because of the upgrade to 16.04 which occurred months ago. If I start a search in Dash the apps are found. After opening the Dash, syslog reports the following:
04.12.16 14:50 steve64bit-EasyNote com.canonical.Unity.Scope.Home (unity-scope-home:2454): unity-scope-home-WARNING **: scope.vala:669: Unable to search scope: timeout was reached 04.12.16 14:50 steve64bit-EasyNote-TSX66HR com.canonical.Unity.Scope.Home (unity-scope-home:2454): libunity-WARNING **: unity-master-scope.vala:114: Unable to search scope: 'timeout was reached'
I have reinstalled unity-scope-home but the problem remains.
EDIT: SOLVED! The problem was Zeitgeist. I purged all zeitgeist installs (zeitgeist, zeitgeist-core, zeitgeist-datahub etc.) except for libzeitgeist-2.0-0 (too many dependencies including Nautilus). I then reinstalled them all and also reinstalled libzeitgeist-2.0-0. After a reboot the Dash is working again perfectly.