OSX 10.9.4 crash when connected to CinemaDisplay & Dock appears

MBP Retina, Mid 2012

Core i7

Boot ROM Version: MBP101.00EE.B02

SMC Version (system): 2.3f35

Connected to LED CinemaDisplay Model # A1267. Using monitor MiniDisplay Port on MBP Thunderbolt port.

Last time I used the CinemaDisplay was many months ago, likely on an older version of OSX and never had problems.

Now, as soon as the dock appears via mouseover, it crashes to the logon screen.

No crash in safe mode.

No crash as long as dock is hidden.

Where could the issue be? A conflicting app?