This falls into the category of “notes I am posting for myself so I don’t lose them”. A Logitech C910 Webcam works under Mac OS X (more or less — some users have had more success than others), but the Logitech Webcam Software is buggy and Logitech seems to be in no big hurry to fix it, as can be attested to by the many posts in their Webcams forum complaining about problems using the device with a Mac. I followed all the instructions in this thread (which was actually for OS X 10.6 but I was grasping at straws) but nothing helped – after I uninstalled and reinstalled the Webcam software, it would run fine ONCE and then after that, every time I’d try to run it again, it would crash immediately after opening. This was not always the case, but perhaps something was broken during an upgrade.
I figured out that if I go into /Users/username/Library/Preferences/ and remove the files com.logishrd.LWS.plist and com.logishrd.LWS.plist.lockfile it would then not crash on the next run attempt. So, Logitech’s software is buggy because the mere presence of these files should not cause the software to crash. Note this is with the lws220.dmg software so if they ever release a newer version it just might fix the problem.
I suppose you could write an AppleScript to delete the two offending files and then launch the Logitech Webcam Software, but I have not got around to that yet (I An Not A Programmer). My question is, why doesn’t Logitech fix their damn software instead of leaving OS X users hanging, waiting for a solution? People have been complaining about these issues for at least a year and a half now!