Incompatible/Invalid saves - No mods

[Viggo]

I was playing KSP on my mac OS X Yosemite, when it crashed, so I restarted it but it wouldn't get past the loading screen.

So I tried restarting my computer, and then Steam said it wasn't installed even though I could open it and such. I "Installed" it again and everything seemed to work properly. But when I  tried to open my save files a small window appeared saying:     Conformation needed,  There are incompatible/invalid saves on your save folder. What would you like to do?   And two buttons saying Delete and Not now.

So I pressed 'Not now' and both of my save files were gone!

I actually realized later on that even if I made a new save it wouldn't be there either, so I really need to fix this.

I've seen the issue with other people but they all had mods or add-ons involved, I've never installed one or anything...  If anyone knows what I could do to fix this, it would be extremely helpful.

Thanks!

Edited March 31, 2016 by Viggo

[Hotel26]

I've just had this occur.

It popped up asking if I wanted to Delete or Cancel.  Because I don't trust such things, I went to my directory for the world I had been playing and made a copy of the quicksave.sfs and then clicked Delete.  The action taken then by KSP was to delete the ENTIRE DIRECTORY containing my world and months of work AND my carefully duplicated quicksave.sfs copy.  All gone.  This was my mainline, production world; all gone.

[I'm on Linux Mint 17.2 64-bit and I run directly rather than through Steam.  I have MechJeb, Kerbal Alarm Clock, Docking Port and Haystack installed.  The upgrade to 64-bits is relatively recent and as a result my normal system backups are not operational, which is why I can't just go and get yesterday's KSP state off another disk.]

This happened after a crash and the crash occurred because I had done an f5 quick save and I began typing ahead before it had finished ['Z' for max thrust].  I've noticed in the far past that you can crash KSP by triggering a Quick Save while an Auto Save is in progress which indicates to me that the code around saves[/restores?] is not sufficiently interlocked.

And the reason I was doing a quicksave during a very long transfer burn is because as of the last couple of months, the nuke engine heat indicators no longer give you a precise warning of when those engines are going to fail.  When the red progress bar for overheat gets level with about the 'v' in Overheat [30%?], the engines explode without warning, effectively ruining your day.  This happens in a vacuum [alt:150K] with the 12 running nuke engines being the only source of heat.

fwiw, the quicksave.sfs looked normal length.  guess the moral of the story is that if you are going to back up anything manually, send it outside KSP's reach.  and whenever KSP offers to Delete anything it doesn't want to deal with, fully expect it to take the whole world down irrecoverably.  you will be better off in all cases, attempting to do diagnosis/surgery yourself, if you have that capability.