Creating the read-only file C:\Windows\perfc.dat on your computer prevents the file-scrambling part of NotPetya running, but doesn’t stop it spreading on the network. Note, the software is designed to spread internally for less than an hour and then kicks in; it doesn’t attempt to spread externally across the internet like WannaCry did.

update:

in folder C:\windows create a file call perfc with no extension and make it read only

also create C:\windows\perfc.dat and C:\windows\perc.dll and also make both files read only.