I have a similar issue on Windows x64, steam. Left list with the vessels in the tracking station is not accessable anymore and I can't "fly" a particular station. If I leave the tracking station and then re-enter I can select other vessels again until I chose a particular one (base on the mün). I had the same issue with another base, but could resolve it because I had a rover close. "Flew" that rover and switched to the base. Now I can use this base again from the tracking station. However the other one is still not accesable. A workaround might be to fly something close and do the same trick. (Not tryed yet) I think this is related to antoher issue ... In the Austronaut Complex I am missing almost all my Kerbals flying on any vessel. Only one of about 10 shows up in the assigned tab. Also, even if fully upgraded I have a max of 12 now, but the description from the outside (right click on the bulding) did read "fully upgraded", "unlimtted number of Kerbals" earlier, after the upgrade. Suddenly I can't see this either when right clicking the building. As with the post before I was using a save from the (steam) version before 1.0.