On all versions it has been deleting my worlds on there own but the files are still in the .minecraft folder. it has been happening on all versions both vanilla and modded and I am getting irritated because I keep rebuilding the map for my school's server. this is effecting me and the school because we cant launch the server without the map and we cant make the map because of this issue. we first started having this issue during 1.6.4 and it has continued all the way up to the latest update please if you can fix this of tell us of why this is happening it would be really appreciated, we know it is not because we are using mods because it is happening to vanilla worlds as well. we love the minecraft experience but we cant play it if this keeps happening. I am unsure if this has already been reported, I didn't find it on this or any other support website and really would like this to be fixed as soon as possible