# Getting Started

This section is intended to give a quick introduction to iDefrag. It isn’t supposed to be exhaustive — for more in-depth information, please look at the rest of the documentation.

## About your license

Tip

You can print your license and keep it safe on paper!

Printed licenses will work just fine when scanned back in or photographed, provided the Q-R code in the top right corner is clearly visible.

When you purchased iDefrag, you were given a license file that looks like this:

Please keep this safe; it is both your proof of purchase and is required to activate the program again should you need to reinstall for some reason.

## Before you start

Warning

Before using iDefrag on a disk, you should back up any important data stored on it.

We strongly advise keeping regular back-ups, if you don’t already. While we don’t know of any bugs in iDefrag that could cause data loss, defragmenting or optimising your disk may expose any faults that exist with your computer’s disk or memory subsystems.

Tip

You can use your Mac’s built-in Time Machine backup software to keep your data safe.

## Authorisation

Mac OS X has built-in security features to prevent applications (and other users) from accessing the disk idrectly. As a result, iDefrag sometimes needs to ask you for permission when you select a disk. When this happens, you’ll see a gold coloured padlock like this:

Click on the lock button and then enter your administrator username and password when prompted. Whenever you see a gold padlock like this, you should check carefully to make sure you understand what permissions you are being asked for and why, and only enter your log-in details if you are sure you know what will happen.

## Main display

Tip

You can’t hurt anything by playing with iDefrag’s user interface. iDefrag will only start working when you push “Go”.

The major features of iDefrag’s main window are annotated above:

1. The “Go” button. This starts defragmentation, or, if defragmentation will require a restart, sets your computer up to boot into the special reboot-and-defragment mode.
2. Using this pop-up list, you can choose which of iDefrag’s algorithms you want to run. Usually you will want to pick “Full Defrag”.
3. Each square in this area of the window represents a single block in your file-system. The colours indicate what kind (or class) of file is using the block — for example, by default, green is used to represent applications. Anything that’s red is fragmented.

Note

iDefrag shades adjacent runs of blocks of the same colour in an alternating light and dark pattern, so you can see the ends of your files or fragments.

4. This part of the window shows a representation of the entire disk. The white area are free space. In this particular example, the disk is not particularly fragmented.
5. The right hand pane of the iDefrag window shows information about the disk, the key for the colours in the central vies, or information about the selected or hovered-over file, depending on which of the buttons at the top is selected.

## Defragmenting your boot disk

Note

Except when using the algorithms marked “on-line”, iDefrag needs exclusive access to the volume you wish to defragment.

If other programs are using the disk, it may not be possible to gain exclusive access. Sometimes you may be able to terminate other programs to solve this problem, but for the startup volume the operating system itself is using the disk and so you will need to use one of the options listed here.

If you pick your start-up volume in iDefrag and hit the “Go” button, you will see a prompt telling you that iDefrag needs to restart your machine. This is the simplest method of defragmenting your boot disk, but it does require around 1GB of contiguous free space.

If that isn’t an option or doesn’t work for some reason, you can use one of the following methods instead:

1. Use the “Create Boot Disk” option under the “iDefrag” menu. You’ll need a working recovery partition on your disk already, and you’ll want an external drive of some sort — typically we’d use a Flash stick for this — on which to create the new boot disk.

2. Attach your Mac to another Mac with either a Firewire or Thunderbolt cable, then put your machine into Target Disk Mode, and start iDefrag on the other machine.

   Warning

   Some older PowerPC (G4) Macs have bugs in their implementation of Firewire Target Disk Mode.

   On affected systems, the Firewire logo may stop moving from place to place on the display; this may also cause iDefrag to display the beachball cursor.

   We recommend that you use a different method for older PowerPC systems.

3. If you have an external drive, or have partitioned your main hard drive, you can install OS X on it and boot from that.

## How can I tell if my disk needs defragmenting?

We typically recommend that you defragment your disk only when you notice that it is running more slowly than it did when you purchased your computer.

That said, you can use iDefrag itself to investigate how fragmented your disk is; the whole disk view is a very useful at-a-glance way to inspect your disk’s fragmentation status… if it’s mostly red, it’s a good bet that you need to defragment. You can also see a variety of statistics in the right hand pane of iDefrag’s window that can help you to decide.

## How long does a typical defragmentation take?

Everybody’s disk is different, so it’s hard to give specific guidance on this, but as a rule of thumb we’d say that 6-7 hours was typical, but for very large, very slow or very fragmented disks, it can take 24 hours or more.

iDefrag itself is pretty fast, so it’s usually the disk that’s holding things up here.

## What should I do if something goes wrong?

Importantly: Don’t Panic!

Most things that could go wrong are easily fixed and don’t require drastic measures such as reinstalling or wiping your disk. If you take your machine to an expert (such as an Apple Genius in an Apple Store) and they suggest this approach, please think twice. It really is very unlikely that whatever problem you’re seeing necessitates this kind of solution.

If something does go wrong and you can’t work out what to do, we recommend that you get in touch. We will endeavour to solve whatever problem you’re having.