Login window empty - MXMC 2.6

Hey there!
Is there any quick fix for the empty login window (see the attached image) at MXMC startup? MXMC crashed during video export. Computer reboot does not help.

We fixed it with deleting the UserAccess.json file in %appdata%\Mobotix\MxManagementCenter folder and importing project back to fresh MxMC.