If anyone wants a problem free environment for backing up, build a dedicated box and install Windows 2000 up to SP3 but not SP4. Install only backup related software & utilities and nothing else. Do not hook up to the internet with this box. Do not install firewalls, Anti Virus or spyware softwares.
Do your updating of your backup programs manually via USB flash drive. Run a virus scan on anything you download to your flash drive before you transport it to your standalone backup box.
No disappearing drives
No conflicts (that can't be isolated quickly)
Nothing but a cruizzzz ... sweet!