The one time OLCI did not work for me I spent about half and hour on the phone with a rep who fixed the problem but could not tell me what the problem was because it was "ageist policy" to disclose that infomation.

As it turned out it was a TSA problem and I had been selected for extra screening, I guess that "ageist policy" means that the airline can not inform you of extra TSA screening.

Other that this I have had no problems with OLCI, and I have used multiple operating systems to check in (Mac at home, PC at the place I am visiting)