Power/Activity LED Behavior for the My Book World Edition drive:
| Appearance | Drive State |
| Power On Sequence | |
| Bottom LED Dimmed | Powering up |
| LEDs light up in sequence from bottom to top | Transitioning to drive ready |
| Normal Operation | |
| Capacity Gauge, steady illumination | Power-on state, ready for use |
| Moving up and down | Drive in use |
| Slow flashing (every four seconds) | System standby |
| Power Down Sequence | |
| Dimming up/dimming down in an odd/even alternating pattern | Drive powering down |
| Device Events | |
| Bottom LED dimmed, top LED flashing | Boot unsuccessful |
| Fast flashing (every half second) | My Book system event, action required |
| Continuous “center out” sweep pattern | Unit failure |
Capacity Gauge:
When the device is turned on, the Capacity Gauge indicates space used on the drive by fully illuminating six sections in an upward vertical direction. Each section represents approximately 17 percent of drive capacity. Because this drive is preformatted, the first section is illuminated upon installation.
Power/Activity LED Functionality for My Book Studio II, My Book Mirror Edition:
| Appearance | Description |
| Steady | Power-on state or power-saver mode |
| Moving up and down | Drive in use |
| Slow flashing (every 4 seconds) | System standby |
| Alternating checkerboard pattern | Transitioning from one state to another |
| Alternate flashing between top and bottom LEDs | RAID Degraded Mode |
| Cycling from bottom to top | RAID rebuild mode |
| Fast Flashing (every 1 second) | Over-Temperature condition* |
* If this condition occurs, read/write activity will stop and the drive will spin down. Disconnect and power down the drive. Allow it to cool down for 1-2 hours and then reconnect and power up the device.
Capacity Gauge:
Because the WD My Book external hard drives are preformatted and contain software and utilities, the first section is illuminated upon installation. The Capacity Gauge is enabled only when the WD Drive Manager program is installed and running on the computer system.
For Macintosh, the WD Drive Manager program can be installed by accessing the WD My Book external hard drive or the installation CD and the clicking on the Mac folder, select the language of your choice, then double-click on the WD Button Manager Software disk image that contains the installer.
For Windows, the autorun menu appears only on the first installation of the drive. If AutoPlay is disabled on your computer or if you are connecting the WD My Book external drive to another computer, you must install the utilities manually. Open up the WD My Book external hard drive or installation CD from My Computer or Windows Explorer. Double-click on the My Book folder, the WD_Windows_Tools folder, and then Setup or Setup.exe.
Power/Activity LED Functionality for MyBook Essential 2.0, Home, Office, Studio:
| Appearance | Description |
| Steady | Power-on state or power-saver mode |
| Fast flashing (for approx. 3 seconds) | Transitioning to system standby or power down |
| Slow flashing (every 5 seconds) | System standby |
| Up and down (excluding Essential 2.0) | Drive in use |
Capacity Gauge:
Because the WD My Book external hard drives are preformatted and contain software and utilities, the first section is illuminated upon installation. The Capacity Gauge is enabled only when the WD Button Manager program is installed and running on the computer system.
For Macintosh, the WD Button Manager program can be installed by accessing the WD My Book external hard drive and the clicking on the Mac folder, select the language of your choice, then double-click on the WD Button Manager Software disk image that contains the installer.
For Windows, the autorun menu appears only on the first installation of the drive. If AutoPlay is disabled on your computer or if you are connecting the WD My Book external drive to another computer, you must install the utilities manually. Open up the WD My Book external hard drive from My Computer or Windows Explorer. Double-click on the My Book folder, the WD_Windows_Tools folder, and then Setup or Setup.exe.
Power/Activity LED Functionality for MyBook Essential, Pro, Pro II, Premium, Premium II, World, World II: The Power/Activity and Capacity Gauge LEDs are two concentric rings on the front panel of the WD My Book external hard drive. The outer ring is the Power/Activity LED and the inner ring is the Capacity Gauge LED.
| Appearance | Description |
| Steady | Power-on state or power-saver mode |
| Fast flashing (for approx. 3 seconds) | Transitioning to system standby or power down |
| Slow flashing (every 5 seconds) | System standby |
| Rotating clockwise | Drive in use |
| Alternate flashing between inner and outer rings | RAID Degraded Mode |
| Rotating inner ring which increments progressively | RAID rebuild mode |
| Simultaneous flashing of both inner and outer LED rings | Device is overheating: Shut down the My Book device |
Capacity Gauge:
The Capacity Gauge (inner ring) consists of six sections which will illuminate in a clockwise direction to indicate space used on the My Book external drive. Each section represents approximately 17 percent of disk space. Because the WD My Book external hard drives are preformatted and contain software and utilities, the first section is illuminated upon installation. The Capacity Gauge is enabled only when the WD Button Manager program is installed and running on the computer system.
For Macintosh, the WD Button Manager program can be installed by accessing the WD My Book external hard drive and the clicking on the Mac folder, select the language of your choice, then double-click on the WD Button Manager Software disk image that contains the installer.
For Windows, the autorun menu appears only on the first installation of the drive. If AutoPlay is disabled on your computer or if you are connecting the WD My Book external drive to another computer, you must install the utilities manually. Open up the WD My Book external hard drive from My Computer or Windows Explorer. Double-click on the My Book folder, the WD_Windows_Tools folder, and then Setup or Setup.exe.
Power/Activity LED Functionality for My Passport Elite and My Passport Studio: The power/activity and capacity gauge indicators are represented by four LEDs underneath the sliding port cover as shown below. Only one LED illuminates at a time corresponding to drive capacity used.
| Appearance | Description |
| Steady | Power-on state or power-saver mode |
| Slow Flashing | Drive Standby |
| Alternating left to right then right to left | Drive In Use |
Capacity Gauge:
Because the WD My Book external hard drives are preformatted and contain software and utilities, the first section is illuminated upon installation. The Capacity Gauge is enabled only when the WD Drive Manager program is installed and running on the computer system.
For Macintosh, the WD Drive Manager program can be installed by accessing the WD My Book external hard drive or the installation CD and the clicking on the Mac folder, select the language of your choice, then double-click on the WD Button Manager Software disk image that contains the installer.
For Windows, the autorun menu appears only on the first installation of the drive. If AutoPlay is disabled on your computer or if you are connecting the WD My Book external drive to another computer, you must install the utilities manually. Open up the WD My Book external hard drive or installation CD from My Computer or Windows Explorer. Double-click on the My Book folder, the WD_Windows_Tools folder, and then Setup or Setup.exe.
