Staying one step ahead
We answer the top FA Qs that could blight your brilliant backup plans
The drive could not be found…
It might sound basic, but your backup drive needs to be mounted and available on your Mac’s Desktop in order to be usable by Time Machine. This applies to both DAS and NAS storage, so if the drive can’t be found, check that it’s connected, powered on, mounted and correctly formatted with a GUID partition map and Mac OS Extended (Journaled) format. Disks formatted for Windows and iPods can’t be used for backup. And of course, you should never move a Mac or a drive around during backup in case the wired connection is severed by a loose cable.
Your backup drive needs to be available on your Mac’s desktop to be Time Machine-friendly
The drive is getting full… What are my options now?
If you’ve been back up for a while, especially with large files, your drive will eventually fill up. Time Machine is pretty clever here, and will delete the oldest files to free up space, using the logic that files you created or deleted a long time ago are perhaps less valuable to you. However this does mean losing some files, so an alternative is to either buy a new backup disk and keep the old one as an archive, or physically copy the existing backupdb folder (wired backups) or .sparseimage (wireless backups) from your Time Machine drive onto another drive, which you then use as an archive. Apple’s Time Capsule actually has an option to connect a powered USB drive to it and then using the Airport Utility, archive the existing contents of the Time Capsule drive to it, which is a neat solution.
The built-in network interface could not be found…
This is rare with networked backups, but sometimes your Mac’s network settings can get confused. From the Finder’s Go menu, enter /Library/Preferences/SystemConfiguration/ and copy the file ‘NetworkInterfaces.plist’ to your Desktop to back it up. Delete the original ‘NetworkInterfaces.plist’ file and restart your Mac. In System Preferences, reconfigure both your network setup and Time Machine and it should resolve the issue.
Some items are not backed up – how do I rectify this?
In Time Machine’s setup, go into the Options > Excluded Items windoww and check that you
haven’t specified something to be excluded that you actually wanted included. If this doesn’t work, download TimeTracker for free (you can get it from charlessoft.com). This lightweight app only works with wired backups, not the sparsebundle format used for wireless backups, but will let you see the size of each backup as well as navigating inside each one to see files. You can always use the Finder to look inside backup folders as well. In the case of wireless backups, this means double clicking the sparsebundle image to mount it.
I have moved a disk, and now I can’t see my backup! What should I do?
Wired and wireless backups use different formats so there are issues with starting with one type and moving to another. Of course you can always do a fresh backup using the other method and both will remain intact on the drive. It’s also possible to copy backupdb folders from one drive to another, with some limitations, though this takes a long time. What you shouldn’t do is change the name of your Mac, because this will force a new backup from scratch. But copying the backupdb folder to a new drive and then re-specifying that drive as a destination should work. If you move from network to local backup you will have to mount the sparsebundle disk image to enter Time Machine, but it should work. If you move from local to network, you can’t keep using the same set of backups.
How do I access backups made on another Mac?
You can browse backups other than those for the Mac you’re working on by holding å while clicking the Time Machine menu bar item and selecting Browse Other Backup Disks. This should reveal all Time Machine backups on your local network or connected hard drives. You should be able to restore items as long as the backups you’re browsing were made with a recent version of Time Machine, though you’ll have to choose ‘Restore to…’ and put them somewhere new. Holding å also provides access to a way to verify your backups.
What if I need something, but I don’t have my Time Machine drive handy?
From OS X 10.7 onwards, the system keeps local snapshots that are stored on your startup
drive when the backup drive isn’t available and as long as Time Machine is switched on. This gives you a ‘safety net’ in case you accidentally delete a file, but shouldn’t be relied upon for long-term data reliability (only really for emergencies). On laptops, a single daily snapshot is stored for each one of 24 hours from the point you boot the Mac. When you enter Time Machine these are shown as pink rather than the regular grey marks. OS X keeps as many as space permits, prioritising their removal or stopping snapshots altogether if disk space is running very low. Use the About This Mac > More Info > Storage window to view the size of current snapshots.
How do I delete every instance of an item from a backup?
Let’s say that you realise one day that you’ve spent months accidentally backing up a large file or folder that kept changing (triggering repeated backups), but that you don’t actually want backed up. Enter Time Machine and locate an instance of that item in a backup. Right-click on it and either select ‘Delete Backup’ to delete only that instance, or ‘Delete All Backups of (the item)’ to remove every copy of it from the backup drive. Once you do this it’s gone for good, so be absolutely sure it’s what you want to do before you go ahead and start clicking.
Time Machine appears stuck on ‘preparing’… Help!
The first ever back up of a system will take a while, and subsequent ones may do too if you have lots of new or modified files, because the system has to scan them all. If, however, you feel sure that a backup scan is taking way too long – as in several hours – you have got a couple of options. Try resetting Time Machine by deactivating it in System Preferences, disconnecting the external hard drive and deleting the file /Library/Preferences/com. apple.TimeMachine.plist from your top level Library folder. Restart your Mac and reset up Time Machine by specifying your drive. If the problem persists, use Disk Utility to verify and repair both the internal and external hard drives. If it’s still broken, it may be a hardware disk problem.
The backup disk image could not be created. What now?
When you back up wirelessly, Time Machine uses a special sparseimage bundle container format to hold the files. If you get the above error, try the following: check your computer name in the Sharing System Preferences panel.
Sometimes a restart and a second try at running backups will fix errors that occur during copying files
It must not be blank or longer than 25 characters and not contain special characters. Time Machine uses this name as the basis of your backup so if it is changed, it will force a new, full backup from scratch.
An error just occurred while copying files – what do I do?
Sometimes, a restart and a second try at running a backup will fix this. If not, make sure that if you’re running any antivirus software that it’s disabled and also has not been set to scan the Time Machine disk. If you’re storing anything on your backup drive other than the backup folder or disk image, exclude it from Spotlight.