OS X Mountain Lion: If Time Machine can’t find your backup disk
Try any of these suggestions.
- If you’re using an external hard disk as the backup disk, check the connection between the disk and your computer. Make sure the disk is firmly connected and plugged in to a power source. Make sure the disk is turned on.
- If your backup disk is connected to your network, make sure the computer and disk are still on the same network, the disk is turned on, and the network is not experiencing problems.
- If you back up to a disk attached to another computer, make sure the computer is not in sleep. If it is, disable the sleep function for future Time Machine backups.
- Open Time Machine preferences and reselect your backup disk. If you erased your backup disk and began having trouble, reselecting it may fix the problem.
- If you’re using a Time Capsule as your backup disk, use AirPort Utility to make sure it is set up properly and connected to your network.
- Click the Finder icon in the Dock to open a Finder window, and then look in the Devices section. Your backup disk should be listed. If the disk is not listed, it may be turned off, defective, or currently unavailable on your computer’s network.
- If you back up to a Time Capsule or other network disk that has a password, the password for the disk may have changed since you designated it as your backup disk. Log in to your computer with the account you were using when you first set up Time Machine, open Time Machine preferences, reselect the backup disk, and then enter the new password.