Save broke

[Tez613]

So i just spent the last 3 days with every spare moment building a space station. When my game starts to lag so thinking it was my computer i restarted it and when i go to open my save it says that there are incompatible/invalid saves and wont let me open my save is there anything i can do to fix it?   There are two sfs files persistent and quicksave

Edited December 31, 2015 by Tez613
Adding more information

[*Aqua*]

Did you restart your computer while the game was still running?

Lag is normal in KSP. The more complex rockets, planes and station become the more lag there'll be.

About your problem:
If you bought KSP in Steam, go to your ...\Steam\SteamApps\common\Kerbal Space Program\saves directory. In there is a folder named the same as your current savegame. Open the folder and look for sfs-files. Those are the savegame files. Are there several or is there only a lonely persistence.sfs?

If there's only the persistence.sfs, what's the file size of it?

Edited December 31, 2015 by *Aqua*

[Tez613]

There are two sfs files persistent and quicksave the persistent file is 1,143 KB and the quicksave file is 930 KB

[*Aqua*]

Backup your persistent.sfs and rename the quicksave.sfs to persistence.sfs. If the quicksave is fine the game should be able to load it but you might lose some progress.

[Tez613]

YES IT WORKED thank you!!!!!!!!!