I have been plagued with this problem for well over a year, and am hoping someone can shed some light on what is going on.
My setup is that I have a Macbook Pro that I use with a monitor while I'm at home, but I take it out of the house on a daily basis. While I'm at home, I backup the machine to a Western Digital MyBookLive network drive, using Time Machine. This arrangement worked just fine for the longest time. But about last year (sometime in Mountain Lion), I started having this issue where every time I'd come home and connect to my local WiFi, TimeMachine would kick in but soon gives me this message:
The backup disk image “/Volumes/TimeMachine/MyMBPro.sparsebundle” is already in use
I've looked far and wide for a proper solution to how to resolve this issue, but not found one.
The temporary solution (recommended by various websites) is always to restart the MyBookLive, either by disconnecting it's power or using it's website to restart, both of which are annoying and time-consuming options, especially on a daily basis. The Pondi website seems to suggest some network drive has been left connected, but that's not the case either.
There has to be a better way. Should I be disconnecting my machine before leaving the house to prevent this message when I reconnect? I've tried sleeping the computer before leaving, but that doesn't help. Neither does trying to "Skip this backup", which takes forever to finish up.
If someone has a good work-around or a suggestion I could try out, I'd really appreciate it.