Have you ever facing the issue with dissappearing personal views? I have a big list with a lot of columns, rows, public & personal views, but without any calculated columns, 3rd party features, workflows or complicated rights, there are only 4 AD groups. One day, some personal views vanished.
If I open SP Designer, I can see some of them with blank "Modified by" field and 0 KB size. Some of them missing at all. When I opened the visible ones (in normal or advanced more, it doesn't matter), they get back their 4 KB size and "Modified by" name, but acting like public.
If I restore the list from backup to some other SC or test mirrored farm, could I simple copy the view back? And do you have any idea what is wrong?