WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
SAI360 - GRC Platforms
TreeSize - TreeSize tells you where precious disk space has gone to.
Aptible - Aptible is a secure, private cloud deployment platform built to automate HIPAA compliance.
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.
Fastpath Assure - Fastpath Assure is a cloud GRC platform that integrates with various ERP systems