Symptoms
The following error mesage is reported during file system backup:
Unknown status (-1) returned from the data sanitization scanner. (\\ServerName\C$\Program Files\PostgreSQL\9.5\data\base\16393\17355)
and
The process cannot access the file because it is being used by another process. (\\ServerName\ADMIN$\System32\CatRoot2\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\catdb -> E:\Buffer\buf\2\1_3219_15282)
Cause
File system backup set with Volume Shadow Copy and CyberSecurity options under Cybersecurity may report the above error for every single file it scans.
Workaround
You may uncheck the option under Cybersecurity category called Perform cybersecurity scan but leave the Volume Shadow Copy on.