Macbook Pro reads External but not Internal Drive

This is the 2nd time I've heard of someone with Seagate hard drive not working in a MBP. What is the model of hard drive.

Hi Halcyon...thanks for the incredibly quick response. It's a Seagate Momentus 2.5" sata notebook internal drive. 500 GB,7200 RPM & 16 MB cache.
Thanks again!

Weird, I have ones of those that I've used in several MBPs...a 7200.4, if my memory serves correctly. Have you applied all the available firmware updates to your MacBook?

I downloaded the firmware update to be sure it was up to date. I connected my original hard drive via external USB as this is the only way I can get my computer to find a hard drive (the new seagate is still internally installed.) I ran the fireware and it said "this computer does not need this update."
The computer is running fine with my old hard drive (or the Seagate) connected via USB so I am guessing that the hard drive is not the problem.
Could this problem be a Ram problem or a motherboard issue? Could it be a simple as replacing the Sata cable?


Also,I forgot to mention...I took the computer to the Mac Store for diagnostics after the initial problem of the computer "hanging."
The technician tried a tester drive and it worked fine. I didnt want to pay the apple price for installing a new hard drive so I told them to put the original drive in and I would replace it myself. After they reinstalled the original drive it worked fine. I used it for about 2 weeks until the computer shutdown and no longer could read the internal drive.
Just thought that info could help.
Thanks
-Count

There was a problem with some of the MacBook Pro's of that era handling SATA II hard drives. You may want to do a search on Macbook Pro problems with SATA II hard drives. It seems that not all MBPs with the same hard drive model were affected.

Your problem may be related to this: article or this thread

Interesting. The problem is,my original drive that came in the computer (Hitachi,160 GB,5400 RPM) is running fine via external USB but even that drive is not recognized when installed internally. This makes me think that it could possibly be a different issue than the SATA II issue others have had.

I found this thread after researching cables: https://discussions.apple.com/thread/2648100?start=0&ts...
I realize this would be a rare issue,but I am starting to believe it is something to think about.

It could very well be the cable...they are super delicate...but the thing is your original drive is seen. Now if your original drive is SATA I then it could be a shielding issue as there have been reports of some MBP SATA cables not being shielded well enough for SATA II drives.

Problem solved,it was the hard drive cable. Thanks for the help Hallcyon!

Glad to help.

This same exact thing happened to me same model and year of macbook, I tried an ssd drive and a seagate momentus 320 and both would only work externally and not show up internally so I am hoping that it might be the same issue with the cable...I just ordered one off amazon so keeping my fingers crossed that it is the same problem!! Glad I stumbled upon this knowing I'm not going crazy

I hope the new cable helps. It would seem that Apple dropped the ball on that one.

I'm having write issues with a new SSD (Samsung 830) installed in a Macbook Pro 15" 2009. Did a new cable solve your problem?
Thanks.