Toshiba External Hard Drive


macrumors member
Original poster
Sep 12, 2009
I just bought a new 1 TB external hard drive for back up purposes. When i connect it via USB to my Snow Leopard macbook pro, it gives me a "this disk not readable by this computer message". I click ignore, and it lets me do whatever i want to the disk - read, write, etc. I have tried repair disk - tells me it's good to go, and tried reformatting several times - thought not zero disk data or the 7 pass bs.

Any ideas?

Also when i connect it to my airport extreme - lets me connect just fine without any bs. Odd....


macrumors newbie
Dec 7, 2009
You may want to try "Partitioning" the disk and not just reformatting it. Many times, external drive come pre-formatted and partitioned for PCs. If you want to use this drive exclusively with you Mac, it would be best to format this HFS+ Journaled and partition it as GUID or APL. Especially for a drive of this size.

Remember, this procedure will erase ALL data on the external drive.

1. Connect the external hard drive.

2. Open Disk Utility.

3. Select the external hard drive in the panel on the left. Make certain you select the proper drive.

4. Click the Partition tab on the right.

5. Change the volume scheme to "1 Partition" (or whatever you prefer).

5. IMPORTANT, and often overlooked: Click the Options button and select "GUID" if you will be using this drive only with Intel based Macs (modern Macs). Select "APL" if you need to use it on PPC based Macs as well.

6. Name the volume.

7. Select "Mac OS Extended (Journaled)" for the Format.

8. Click Apply.

Hope this works,


macrumors newbie
Jan 23, 2009
just to add to this very old thread:

i had exactly the same problem.
till i found out that when i connect the drive it also wants to mount a crap called "TOSHIBA Virtual CD Drive Media". Probably NTFS formatted, but this is in fact the drive that throws the error. It's impossible to erase this partition, because the drive's controller controls it, as i read in another forum.

toshiba used to provide a tool to remove it but i couldn't do it running parallels.

bye toshiba, unbelievable...

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