Update: "Magically," the backup is working over AirPort Disk. I'll chalk it up to a Snow Leopard ghost. I have been backing up to a WD My Book 1TB drive connected to my Airport Extreme router without any problems. Yesterday I upgraded to 10.6 (installed over 10.5.8, not a clean install) and have been having problems with Time Machine since. After the OS finished installing, I attempted to perform a wireless backup. Everything mounted properly, and it began a 10GB backup. When it got to around 5.8GB, Time Machine came up with a network error message (not sure which one exactly) and stopped the backup. At this point I just connected the drive directly to my computer to perform the backup, and it did so without any hiccups. But now I can't even connect to the AirPort disk, let alone try to backup to it. Time Machine says it's not configured, and when I try to browse for my Time Machine Backup Disk it won't let me select it, even though the drive shows up in AirPort Utility. I've enclosed a screenshot of what I'm seeing. Does anyone have any tips to help me get this mounted and working again? This is not turning out to be as painfree an update as advertised.