Adjusted the clock back one hours and was able open it again. Checked the wasteland and the LVL 52 dweller just found 25 caps. I recalled the dwellers and collected it. The game was saved.
Bethesda is very bad in this case, it is quite obvious that the crash was cause by the level 50+, but instead of fixing the problem, they blame the players for changing the time. If I can find the problem out by the above test, Bethesda can find it too.
Don't forget the "level 50+ dweller" is created by Bethesda in the December update. They do not test and make sure no bug before launching the update.