The following problem is solved! Problem was a mod (H.O.M.E.) Steam updated my KSP to 0.25, when i try to play it loads to 100% and crashes. There are two tasks open, one named kerbal space program, the other named Oops! and a window asking for tracking my stats I´m running 32 bit WinXP duo core this is a part of the error dump: Unity Player [version: Unity 4.5.2f1_9abb1b59b47c] KSP.exe caused an Access Violation (0xc0000005) in module KSP.exe at 001b:007960c8. Error occurred at 2014-10-08_230948. X:\Auslagerung Programme\SteamLibrary\steamapps\common\Kerbal Space Program\KSP.exe, run by Hundl. 75% memory in use. 3583 MB physical memory [890 MB free]. 0 MB paging file [2742 MB free]. 2048 MB user address space [61 MB free]. Write to location 00000000 caused an access violation. Context: EDI: 0x00000000 ESI: 0x00000000 EAX: 0x00000000 EBX: 0x00000000 ECX: 0x00000000 EDX: 0x006f6e6f EIP: 0x007960c8 EBP: 0x089bfe80 SegCs: 0x0000001b EFlags: 0x00010206 ESP: 0x089bfe00 SegSs: 0x00000023 Bytes at CS:EIP: 89 14 81 8b 55 c4 01 55 dc 40 ff 4d d4 89 45 d0 Hope it is a common bug and i get a hotfix. And i do hope this will not be the next game which updates to a non executable like take on mars did for me