I've seen this effect with various protection softwares. My best OS upgrades seem to be when I uninstall the antivirus suite and other protection software. We'll reinstall such when the OS is done upgrading.
My parents have an HP laptop with vista 4GB RAM, 320 HDD. I was trying to install a windows 7 upgrade. When win 7 installation did the compatibility check, it reported that the hard drive was almost full (3 GB free) and could not proceed. I quit the installation and tried to figure out what was eating up so much hdd space. I looked at all the folders on C drive. I even told windows to show hidden files and system protected files. I could not find the offending files. I then decided to do a fresh install of win 7 and format the hdd to remove all files. Before doing that I downloaded Belarc to see what software was installed on the laptop and make sure I had the installation media. When I got the report, it reported 255GB free. Somehow the hard drive was not full like it had been. What?s strange is that it?s not usually all that full. Then it was full then not full. What I?m wondering is what would cause the hard drive to report almost full. Could it be a hardware problem? Might it be an issue with windows? Should I be worried? Is Vista trying to protect itself and keep me from upgrading? In the end I decided to wait on the upgrade deferring to Vikings football.
Do I chalk this up to a software glitch in Vista? Bad installation media or should I panic about a bad drive?