WPR Mac Help

In my last post, I talked about how to create a full and complete backup of your Mac’s hard drive. With this you can restore your computer to exactly what it looked like when you created the backup. This comes in very handy if, for example, your hard drive was replaced or you did some major software upgrade and you just didn’t like the way it went. I’ve used this procedure when I’ve upgraded to a larger hard drive in a machine.

This article is about how to use that backup you’ve made to restore some or all of your data.

If you’ve followed along in the last post, “Ultimate Backup Creation“, you should have a disk image sitting on your external hard drive. A disk image is just a single file that’s a picture of what your hard drive looked like when you made it.

There are probably two different cases where you’d want to restore some files. The first, you just need a couple of specific files or folders. You know, “Oh drat! I threw away that folder with all my vacation pictures in it!” That kind of stuff.

The other situation is the “Oh man! This is reeeeeaaaaaaaaalllllly bad…” Maybe you have an update that seems to have botched up your whole system. Or you have a laptop that went in for repair that they “helpfully” replaced your hard drive for you. Either way, you’re looking to take your Mac back to what it looked like when the sun was shining, the grass was green, and had just made a backup of your nicely working Mac.

Retrieving Specific Folders

Let’s start with the easy one first, shall we? You’ve got a folder or file (or two) that you just want to retrieve. Simple enough! Remember how I said that disk image file was a complete picture of your hard drive? Just double click on it and it will “mount” on your desktop. It will have a generic white icon like this:

You can now rummage around in there and see if you can find your files. You’ll probably want to start by looking in the “Users” folder, as that’s where most of your things live. Anything you drag out of this “disk” will be copied to the location you drag it to. (Because that disk image cannot be modified. It was created as read-only.)

When you’re done, drag this “disk” icon to the trash to eject it. The original file will still be right where you left it, so you can double click on it at any time to go back into it.

Catastrophic Recovery

Now let’s take the harder case: For whatever reason, you want to wipe out the contents of your hard drive and put things back to where they had been when you made your backup. Actually, it’s not really all that hard.

1. Boot from some other disk

First we’ll start the computer from some other disk. Dig through your drawers (or if you’re me, go into the “Baffling Vault of Antiquity”) and find your OS X install disk. You’ll need a disk from either 10.3 or 10.4. This might be the disk that came with your machine, or it might be the disk you bought when you purchased OS X.

To start the computer from this disk, put it in the CD/DVD drive and restart your computer. Hold down the “C” key. It should start up in the Mac OS X installer. If it didn’t, you’ve either got the wrong disk or your computer didn’t see you holding down the “C” key early enough. Restart the computer (holding down the “C” key).

When you get the machine started from the CD, it will take you into the OS X installer. We’re not actually all that interested in installing OS X. This just gives us the opportunity to wipe out and restore our Mac’s hard drive. If we’re booted normally (from the hard drive itself) , it won’t let us do that. (And thankfully so.)

You don’t have to use the installer disk for this if you have some other kind of boot drive. But since everyone will have an installer disk (they come with your Mac or with your copy of OS X), I’ll talk about this option.

2. Start up Disk Utility

Disk Utility can be run from the installation CD. It’s pretty handy for those times when you need to do some serious work on your start-up disk. Once you’re in the OS X installation screen, click on the “Installer” menu and pull down “Disk Utility”. This option has a tendency to move around in different versions of the installer disk. You might have to do some hunting, but it should be hanging out in one of those menus.

3. Copy Your Data Back

When you open up Disk Utility, you should be in some familiar ground again. If it’s not all ready, make sure the hard drive with your backup archive is turned on and connected to your computer. You should see both it and your computer’s start up disk in the column at the LH side.

Now we’re going to take that copy (disk image) you made of your hard drive and put it back. Keep in mind, this procedure will wipe out EVERYTHING that’s currently on your hard drive in favor of what’s in your backup. (If we check the right box. More on this below.) That’s why this is only for real catastrophes or something you really planned on doing.

The great news is that restoring all of this takes significantly less time to do than making the backup. On my machine, that 99 GB takes about 20 minutes.

First, we click on the picture of your hard drive in the LH column. On the RH side, we should now see a panel that has some tabs running across the top. One of these is “Restore”. Click on this tab.

In the “Source:” filed, we’ll be telling it which backup image has our data that we want to restore. If we click on the “image” button, we can go find our disk image that we created last time on our external drive.

The “Destination:” field doesn’t have any buttons. What’s going on? In this case, we drag the picture of our hard drive from the LH column into the empty field. In my case, this is called “Macintosh HD”.

 

Erase Destination?

 

This little check box is pretty important, so let’s talk about it more in depth. If you do NOT check it, then your current data is left where it is. When you perform the restore, it will over-write any files with files of the same name from your backup.

So if you have “File A” on your desktop, and you also had “File A” there when you made your backup, the version from your backup will be the one you end up with. Any changes you made to “File A” since your backup will be lost. Files that are currently on your hard drive but not in your backup are left alone. So if you made “File B” after you made your backup, “File B” wil still be sitting right where you left it.

At first blush, this might sound ideal. But there are some problems. If you had some trouble and you’re restoring to get rid of that trouble, you might still have some icky files around when you’re done that continue to cause trouble. Also, restoring this way is significantly slower–hours instead of minutes.

If you DO check the box, then it does just what it says it will. It erases your entire hard drive first, and lays down the data from your backup. You end up with your hard drive looking exactly like it did when you made the backup. Everything you did between when you made your backup and now is lost. Erasing the drive first also allows the restore process to go much faster.

How do you know which to do? If you just made that backup or you know that you have newer files elsewhere or don’t care about any files you created since then, your best bet is to erase the drive. If you think you have files on your hard drive that you don’t think are in your backup, then don’t erase. If the restore doesn’t fix your trouble, then go back and restore again with the “Erase Destination” box checked.

In this example, I’m assuming that our backup is fairly current, or any non-current files are sitting around elsewhere, like in our regular daily backup. (I promise I’ll blog about this soon!)

When we have both the source and destination fields filled in, we click the “Restore” button. It may ask us for our password. You will see a little progress bar go across the window. If you selected the “Erase Destination” box, it will say “Copying Blocks…” In a few minutes, your hard drive is back, exactly the way you had it when you made your backup.

4. Testing and Checking

Now that you have your drive restored to it’s former glory, you might want to take a moment and make sure it all landed OK. We just pushed around a whole lot of 1’s and 0’s. Click back into the “First Aid” tab. Click on your hard drive icon, and click the “Verify Disk” button. If there are any errors, try the “Repair Disk” button.

Finally, restart your computer as normal. If you’ve booted from the installer disk, you can do this by choosing “Quit” from the Disk Utility menu, then the Installer menu. Open up Disk Utility again (this time, from your Utilities folder). Click on your hard drive again, then click the “Repair Disk Permissions” button under the “First Aid” tab. Don’t be alarmed if you see a whole lot of things fly by.

At this point, your computer should be running exactly as it was when you made the backup.