I have a brand new installation of Avast Premier on Windows 8.1. I’ve tried twice to use the Data Shredder to clear unused space on a 2TB primary system drive. The problem that occurs is that many of my other applications such as Microsoft Outlook and Word stop responding. Even when I attempt to kill the application process, they all just hang. I only get to the “Cleaning Cluster Tips” in the shred process (18%) when things bog down.
With a 3 TB hard drive, it takes a long time. So far each attempt gets me to about 15% in roughly 8 hours and then it all grinds to an unresponsive state. No other applications can be used.