Some people have reported that after updating to OS X 10.9.2, their internal iSight camera has stopped working. In addition to the camera not working, the CrashReporter process may begin to consume 100% of the CPU while writing error logs for VDCAssistant, because it is crashing every second. Traditional troubleshooting methods don’t seem to help (resetting NVRAM/PRAM, resetting SMC, reapplying the 10.9.2 Combo updater).

Apps that can trigger the VDCAssistant to begin crashing include Google Chrome, or any other app that accesses the iSight. This has also been reported with third-party USB webcams.

A bug report has been filed with Apple, but currently there is not a workaround. This is not affecting the majority of users that have updated to OS X 10.9.2. A few people have posted that reinstalling Mavericks from the Recover Disk partition has fixed it, but this has not worked for everyone.

If you delete /System/Library/LaunchDaemons/ and reboot, it will prevent the VDCAssistant from crashing, but deleting Apple system Daemons is not ideal. See this Apple discussion thread for more details: