Symptoms
C:\System Volume Information\FileProtector\FileStorage\ consumes a lot of drive space.
Cause
This is the file protector (component of Acronis Active Protection feature) snapshot folder. Normally, Acronis Active Protection should only use about 10% of system drive capacity.
The folder is cleared on every "file_protector" driver session start / stop. It might grow in size if the cleanup could not complete and old files remain in the folder.
Solution
Start Acronis Active Protection Service (in Search, type Services and click Services, locate Acronis Active Protection Service and click Start service); the driver will clean the old files and this will fix the issue.
You can also remove these files manually (SYSTEM rights are be required).