Strange issue, I have been using FDM for several months and just upgraded to Windows 7 Ultimate. When I first upgraded, I ran into the known issue with Win7 where it doesn't like to write to NTFS partitions it didn't create...no biggie, I just pointed the download location to a folder on my Win7 drive and the problem went away.

As of a few nights ago, I started getting the error "Failed to access the files on the disk. Check if disk is full or write protected." I made sure there was plenty of room on the drive (45Gb available) for the 4Gb of downloads. I completely opened the folder security for the download folder (everyone able to read/write/modify including subfolders). I tried opening FDM with run as administrator. No luck...

Any ideas?

Edit: Sorry, should have put that I am using FDM 3.0 build 848.

Edit #2: I just tried it on my Win XP Pro install (quad-boot on this system) and it works fine. Win7x64 failed miserably with same failure. I didn't bother with WinXPx64 since WinXPx86 is working fine.