Sparse bundle already in use
I get this error message when I try to back up my IMAC to my time capsue using Time Machine. " The backup disk image â/Volumes/Data/ iMac.sparsebundleâ is already in use." What can I do? Before this happened, I had to shut down the computer because the back up was locking up my computer and I could not access files or even get my computer to respond. after it rebooted my IMAC works, but the back up doesn't and apparently was not backing up most of the day, since it says the last back up was at 8 am this morning and it is supposed to back up hourly. HELP
iMac, OS X Mountain Lion (10.8.1), Time Machine Airport problems