Hermetic File Monitor is for detecting changes to files in a folder, and for detecting additions or deletions of files in a folder. Multiple folders can be set up to be monitored. Optionally files in all subfolders of a folder can also be monitored. Optionally all files can be monitored or just files with a certain file extension such as 'xls'. Folders can be checked automatically at regular intervals. Results can be written to report files.

Hermetic File Monitor works by recording digital signatures of files (using the MD5 message digest algorithm). If the digital signature of a certain file is the same at two successive recordings then the file has not changed. If the digital signature changes then that shows that the contents of the file have changed.