Avast cannot scan its own files

I have 94 files Avast cannot scan because “the system cannot find the path specified”. They are all Avast files, and all begin as follows:
C:/Program Files/AVAST Software/Avast/defs/15122102/
What should I do?

"the system cannot find the path specified"
This scan error is usually gone if you reboot and scan again

also see this https://blog.avast.com/2014/02/28/how-do-i-handle-files-that-avast-cant-scan/