After I upgraded to Mountain Lion I got an error every time I tried to backup over wireless. I figured I would just backup from scratch, therefore I connected the hard drive to my USB, deleted the sparsbundle and then connected the hard drive back up to the Airport Extreme.
Now every time I try to backup wirelessly I get these errors (using Time Machine Buddy):
Starting manual backup
Attempting to mount network destination URL: afp://**********;AUTH=SRP@****%20******._afpovertcp._tcp.local/Time%20Machine
Mounted network destination at mount point: /Volumes/Time Machine using URL: afp://**********;AUTH=SRP@****%20******._afpovertcp._tcp.local/Time%20Machine
Creating disk image /Volumes/Time Machine/*****.sparsebundle
Error 60 creating backup disk image
Failed to create disk image /Volumes/Time Machine/*****.sparsebundle, status: 60
Backup failed with error: 20
Ejected Time Machine network volume.
My setup is an airport extreme base station with a Western Digital Drive connected to it. Of note, two other computers (both Lion) backup to this drive wirelessly via time machine and continue to do so flawlesly.
Please help discussion board, you're my only hope!
MacBook Pro (15-inch 2.4/2.2 GHz), OS X Mountain Lion (10.8.1)