can't open slingshot

[humunculus]

since today (after a reboot) i could not open slingshot as user.

Klicking in the top left button of the desktop does nothing (using German localisation - I guess the Button is called "Application" in English) , and launching it from shell only gives me
some warnings:
slingshot-launcher
[_LOG_LEVEL_INFO 13:46:52.830733] Application.vala:155: Slingshot version: 0.8.1
[_LOG_LEVEL_INFO 13:46:52.830795] Application.vala:157: Kernel version: 3.13.0-57-generic
[_LOG_LEVEL_WARN 13:46:52.836327] Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-Cv9SIL8kMz: Connection refused

Opening it as sudo, gives me more warnings, but it opens:
clemo-HP-EliteBook-8560p% sudo slingshot-launcher
[_LOG_LEVEL_INFO 13:47:16.022837] Application.vala:155: Slingshot version: 0.8.1
[_LOG_LEVEL_INFO 13:47:16.022901] Application.vala:157: Kernel version: 3.13.0-57-generic
[_LOG_LEVEL_WARN 13:47:16.041185] Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-Cv9SIL8kMz: Connection refused
[_LOG_LEVEL_WARN 13:47:17.290392] [Gtk] Invalid icon size 64
[_LOG_LEVEL_WARN 13:47:17.290475] [Gtk] Invalid icon size 64
[_LOG_LEVEL_WARN 13:47:17.293989] [Gtk] Invalid icon size 64
[_LOG_LEVEL_WARN 13:47:17.294098] [Gtk] Invalid icon size 64
[11:47:17.388101 Warning] [DesktopFileInfo] Unable to create AppInfo

[humunculus (3-clemens)]

after another reebot it's working again