KSP and CKan does not start and gives an error message

[PaisteP7]

https://imgur.com/a/GEuyNXU

Hi, 

I have a strange problem since today.  I played KSP yesterday without any problems. When i try to start it today i get an error message from steam : An error occurred while updating KSP (invalid platform). 
 

Unfortunately, since today, CKan has also stopped working.  It cannot be started and an error list appears. as 1st and 2nd is there: unhandled exception : a device connected to the system does not work.

 

I have no explanation for the problem, mainly because I haven't changed anything since yesterday.  no updates installed neither from mods nor from Steam, KSP or CKan.

 

a photo of the CKan error list can be found under the link
 

how can I fix this ? thanks 

[HebaruSan]

It looks like your disk is failing. Back up any important data before it fails completely and replace it.