"Windows error number 3"

I got this problem a while ago but have not had the time to investigate. I´ve been trying to figure it out for a couple of hours now but cant figure it out.

Problem:
I do a snapshot of the primary. The process ends with a notice that there was over 300 000(!) errors.

• It wont boot to the secondary snapshot (of course) It just hangs in a black screen.
  
• I have completely uninstalled InstantRecovery and reinstalled.
• I have turned off Webroot protection but nothing seems to help.
• I am not 100% sure but I think this problem started when I migrated to a SSD from SSHD and that was about the same time as the .302 build was released. Could that have anything to do with it? No problem with IR on the SSHD.
• I can not find any info on "Windows error number 3"
• I might add that I had problems with Macrium too. I got errors there too. But that was solved by changing the target drive for the backup image (simply another hard drive)

Any ideas?

I have a fully updated Windows 8,1 Sandisk SSD 256GB with over 200GB free.