Explanation of hard disk drive clicking sound - ThinkPad General
Symptom The hard disk drive in your ThinkPad system may periodically emit a soft clicking sound. This sound may be more noticeable on hard disk drives manufactured by Hitachi
Affected configurations Any ThinkPad system.
Solution None. This is not a problem. The hard disk drive is working as designed. See the Additional information section below for more details.
A new firmware update has been released for Hitachi DK23CA hard disk drives to reduce the sound level of this clicking. Please note that this firmware will only reduce the sound and will not completely nullify it.
Please check the file download section in this site to see if your hard drive is applicable for this firmware update.
Additional information This clicking sound is caused by the hard disk drive unloading and loading its heads. The head is designed to be periodically unloaded for various reliability reasons. When the hard drive is accessed (either by action from the user or by the operating system), the head will be reloaded. This unloading and loading causes this clicking sound. This is a normal sound and the hard disk drive is working as designed.