Starbound refuses to launch out of STEAM.

Hey guys I wont be long. My starbound 1.0 wont launch out of steam, when I opened it out of the program files but I want to play with my brother which I can not do that way. When I click play on steam it will go up to saying "syncing," then will just stop entirely without a crash report. I have tried deleting and reinstalling deleting resetting the computer than reinstalling, but nothing will work. But it will work on the unstable version but my brother would prefer not to be crashing all the time, which is what his computer does everytime we play unstable mode. Someone please help....