Prohibitory sign even on external hd

[Itsahudak]

I have a mid 2010 13 inch macbook pro. It has a seagate baracuda i bought last year. It was running super slow and then froze completely. On restart got prohibitory sign wouldnt boot to safe mode got into recovery but hd not listed. I have a version of mac on an external hd but even that gives me the prohibtory sign and now trying to get into recovery wont work unless i choose it with option on the start up options (which shows my internal hd there)and then the apple shows up and the bar fills slowly then hangs when its completely full. I would beleive i have faulty hardware but i thought that sign ment software faliure, im just confused on why my external hd which i know works would show that sign as well.

 

[Velin]

On restart got prohibitory sign wouldnt boot to safe mode got into recovery but hd not listed.

If it's the circle with the line going through it, that usually means you've picked a MacOS startup disk -- but it's an OSX version your 2010 Macbook Pro can't use. That's usually what it means, you could have a special situation or circumstance where it means something else. Not sure about the external HD bootup, perhaps there's also a port/cable issue (unlikely, but need to consider all possibilities).

Have you tried booting into Apple Diagnostics mode? Give that a try, simple press and hold "D" from a cold boot. Make sure the external HD is disconnected. Hopefully this is available on a 2010 machine, can't remember back that far.

If you have another Mac with either Firewire or Thunderbolt, you can Target Disk Mode into your 2010 Macbook Pro to at least get all your data off the machine. And from Target Disc Mode, you also could wipe and reinstall whatever the latest version OS works on a 2010 and then try and boot it from the internal HD. I've fixed several stubborn Macs using TDM.

 

[Fishrrman]

It could be a failure of the internal drive. Then... replace the drive.

It could be a failure of the ribbon cable that connects the internal drive to the motherboard. When the cable fails, it "looks like" the drive is failing (to the user) -- but it's really just the cable. This can be ascertained by taking the drive OUT OF the MBP and connecting it externally. If it then boots right up, it's reasonable to assume that the cable is at fault.

 

[Velin]

It could be a failure of the internal drive. . . . It could be a failure of the ribbon cable that connects the internal drive to the motherboard.

Eh, if it was either of these, I think the user would receive the following warning symbol:

But instead s/he received the following warning symbol:

The second symbol indicates wrong or incompatible operating system, not hard drive failure. The "no" or "prohibitory" symbol is pretty specific in Apple land.