You are here:

Macintosh OS/won't show external hard disk drives


QUESTION: Hello there!

For some time I couldn't eject external HDD's but through Disk Utility.

I installed DoubleCommand (to get a forward delete key). It didn't work properly and I couldn't uninstall it.

I wanted to use one HDD I use with Time Machine, for plain backups. I tried to format it, but that didn't work. It worked on a PC -- but I couldn't find it on my Mac but through Disk Utility.

Now, I even can't see my other HDD but through Disk Utility.

I don't know what to do.

I want to make backups and reinstall everything completely (except for DoubleCommand and some other apps).

Version 10.6.8
MacBook5,2 (Mid 2009, MC240*/A)
2,13 GHz Intel Core 2 Duo

Maintenance!? Like..??

Thank you in advance!!

Kind regards,

ANSWER: MacBook 2.13Ghz -

External drives connected how - USB2 or FireWire 400?
Cables can be bad - same works on Windows what ver, model, connection type.
I suspect Firewire on Mac and USB on Windows - external HD has both???

Simpleton Maintenance - Start in Safe Mode (SHIFT key down at boot)
What is Safe Boot, Safe Mode?

If they are partitioned and formatted for Macs, and they eject in Safe Mode,
You have something installed that is grabbing the drives and not releasing them.

If not, Download and Install the 10.6.8 COMBO update - no files will be lost (you DO backup?)
But most system files will be updated.

AppleJack would be my first pick of 3rd Party Maintenance
Onyx would be second, YASU third.

I collect Mac Tech Articles here


My Newest Website -

---------- FOLLOW-UP ----------

QUESTION: Both external drives only work with USB.

I can't go online anymore on my Mac after I tried Safe Mode and logged in with my username and password (I hope that's normal).

I was using one HDD with Time Machine which I've formatted it on a PC.

I hope I can still back up my files somehow, or save my MacBook at least.

Starting up in SAFE MODE is for the repairs that are done. Restart normally after a SAFE MODE startup. Your description of symptoms and steps taken should be more detailed.

Where the external was formatted is unimportant, HOW it is formatted is critical.
A Drive can be PARTITIONED as MBR (WIN), APT (old Apple), or GUID (new Apple)
A Drive can be FORMATTED as FAT32 (WIN & MAC), NTFS (WIN), or HFS+ (Apple)
A Drive can be connected with USB2 (SLOW), USB3 (FAST), Firewire 400 (MEDIUM), FIREWIRE 800 (FAST, THUNDERBOLT (FASTEST), eSATA (FASTER) NOTE the computer and hard drive must have the same type of port to connect.

A USB2 hard drive, formatted MBR(WIN) can be saved to and read from on a Mac BUT CAN NOT be repaired by a Mac, only a PC. It is a very poor choice.
Time Machine automatically sets up an external drive to work

5. I just bought an external drive. How do I get it to work with Time Machine?

21. How do I set up Time Machine to an internal or directly-connected external HD?

Macintosh OS

All Answers

Answers by Expert:

Ask Experts


David Anders


Seattle - The Computer Guy - 15 yr veteran Mac/PC/network problem solving. Clients are design firms, artists, freelancers and photographers. PLEASE PLEASE provide EXACT info for Mac Model and OS Version. RAM installed - added cards - external devices - recent changes. Do you do MONTHLY MAINTENANCE? With what Utility? What you have tried and what result do you want.


First computer experience 1969. Worked in 3 computer stores. Setup First Mac and First IBM-PC.

©2017 All rights reserved.