After installing ESET and setting up Anti-Theft:
This issue occurs most frequently on Dell computers when permissions on the C: folder are set to be inherited from a non-existent parent folder. ESET attempts to add its Anti-Theft permissions to the C: folder and it causes the inherited permissions to disappear. Dell has been made aware of the issue.
If you are experiencing symptoms of a permissions issue on your computer like those described above, contact ESET technical support to have a technician assist you in restoring permissions on your system.