I recently installed a SSD in my MBP and I had problems keeping the spinning hard drive in sleep mode. You can follow this guide to decrease the amount of time it takes for the hard drive to sleep. The default is 10 minutes which is way to high. You can either use Cocktail or use the "sudo pmset -a disksleep X" command in terminal(replace x with number of minutes). Then you need to disable spotlight to prevent it from waking up the drive every 5 minutes. There are two methods to do this: 1. Adding the volumes on the HD to spotlight privacy list in system preferences: doing this disables searching altogether for those volumes. you won't be able to search the HD contents at all. 2. Using terminal to disable indexing: you will still be able to search using spotlight but it will be significantly slower. The second method alone did NOT work for me. For some reason, Spotlight kept waking the drive up every 5 minutes or so. Doing both did the trick. You can check to see if both indexing and searching are disabled by using the "sudo mdutil -a -s" command. The output should look something like this: Code: /: Indexing enabled. /Volumes/BOOTCAMP: Indexing and searching disabled. /Volumes/OS X Data: Indexing and searching disabled. /Volumes/Win7 Data: Indexing and searching disabled. /Volumes/iHD Clone: Indexing and searching disabled. Now, download and install Apple CHUD Tools. Then search for SpindownHD and open it to monitor the status of your drives: (Don't worry about the "Disk sleep after 10 minutes idle" checkbox. It seems broken and doesn't affect the value we set in Terminal) If at this point the HD sleeps properly then you're in luck. For me, the drive woke up once in a while for no apparant reason. Also, everytime you open an open/save dialogue, it starts spinning. To make sure that the OS doesn't wake up the HD by mistake, you need to do two things: 1.Mount/Unmount the drive as needed: There are numerous toturials about this on the web, but the best one which I found that utilizes Growl for noticifications is this: (Credit goes to here) Just replace "iHD Clone" in the first line with the name of one of volumes on the HD. This script mounts/unmounts all the volumes on the HD and then notifies Growl. If you're using Alfred or a similar app, you can add this script as an extension which then you can launch by a couple of keystrokes. 2.Prevent OS X from automounting the volumes at boot: To do this, you need to create a file by the name of "fstab" in /etc. Let's say you have three volumes on the HD. Two of them are formatted with HFS and one with ExFat. Open terminal and enter "sudo pico /etc/fstab". Then write this in the pico text editor: Code: UUID=1522294B-79B4-3F5E-B02B-52032B4DF645 none hfs rw,noauto UUID=B5F04909-36E4-30D4-B1D4-8321A831D240 none hfs rw,noauto UUID=494833FE-64F7-3B84-B9B1-4F89118B54AA none exfat rw,noauto To find the UUID of your volumes, open Disk Utility then select the volume and open the info window by pressing cmd+i . Then, replace the example value above with the UDID of your volume from the info window. You also need to specify the file system of the volume just like the example. For HFS+ or HFS+ journaled use "hfs" as the file system value. For FAT32, use "msdos". For ExFat, use "exfat". Save the file (control+o) and then exit (control+x). Now restart. Then open Disk Utility to confirm that the volumes are unmounted(grey). That's it. Enjoy your perfectly silent MBP with increased battery life!