I purchased the ioSafe Solo periph. hard drive to back-up my data & have also been using ZoneAlaram Free for many years (quite happily too).
Now I find that ZoneAlarm seems to have an interaction with my ioSafe.
Once I've backed up my Computer (windows 7, Dell DataSafe Local Backup) onto the ioSafe, and try to eject it so I can turn it off, I get:
"Problem ejecting USB mass storage device.
This device is currently in use. Close any programs or windows that might be using the device, and try again."
Once I've removed the data from the ioSafe (re-formated), uninstalled ZoneAlarm, and restarted the computer, the ioSafe can be safely ejected & turned off.