Work under permit 4919 and possible missed stuff from 4917:

corner station

quit IOC
C:/SlowControls: svn update
H1ECATC1: PLC3: 'Update from source'
C:/SlowControls/Target/H1ECATC1/H1ECATC1.tsm: PLC1 rescan project, PLC3 rescan project; Actions -> Generate mappings, Check configuration; Save
Copy C:/SlowControls/Target/H1ECATC1/H1ECATC1.tsm to C:/SlowControls/Scripts/Configuration/H1ECATC1/SYS/H1ECatC1.tsm. svn commit
C:/SlowControls/Target/H1ECATC1/PLC3/PLC3.pro: rebuild all, save
Copy C:/SlowControls/Target/H1ECATC1/PLC3/PLC3.pro to C:/SlowControls/TwinCAT/Source/Interferometer/Corner/Plc3.pro
C:/SlowControls/TwinCAT/Source/Current/Interferometer/Corner/Plc3.pro: Export EXP. svn commit Plc3.pro and Plc3.exp.
C:/SlowControls/Target/H1ECATC1/H1ECATC1.tsm: PLC3 rescan project; Actions -> Generate mappings, Check configuration; Save.
Copy C:/SlowControls/Target/H1ECATC1/H1ECATC1.tsm to C:/SlowControls/Scripts/Configuration/H1ECATC1/SYS/H1ECatC1.tsm. svn commit
H1ECATC1: SYS, PLC1, PLC3: 'Stop', 'Update from source', 'Compile': Compile failed.
C:/SlowControls: svn update
H1ECATC1: SYS, PLC1, PLC3: 'Stop', 'Update from source', 'Compile', 'Activate and run': TwinCAT PLC Control has stopped working
Restart computer
quit IOC
H1ECATC1: SYS, PLC1. PLC3: 'Stop', 'Update from source', 'Compile': TwinCAT PLC Control has stopped working
H1ECATC1: SYS, PLC1. PLC2. PLC3: 'Stop', 'Update from source', 'Compile': TwinCAT PLC Control has stopped working, 'Activate and run': TwinCAT PLC Control has stopped working

At this point I don't know what is going on. Going into deeper investigation...