721      iPhone_iPad_Mac_apple

Prohibitory(No entry) Sign after installing new...

Good day,

I have a Macbook pro 13" Mid 2012 Unibody.

It is running the latest OS X Sierra.

I have modified the following specs on the laptop successfully.

• I upgraded the RAM to 8gb 2 years ago.
• End 2016 I upgraded the Primary HDD to a Samsung 840 Evo SSD(Used a cloning program to clone old drive and worked successfully)
• Replaced the dvd drive with a secondary HDD. I used the Apple HDD to replace it.

This all worked 100% on my mac until about a month ago. Then suddenly the mac froze and restarted. After that it started to show a prohibitory sign at startup. I investigated this and all I could find is that it means the OS cannot find a bootable drive. So I reformatted the SSD and tried installing OS X Sierra again. This did not work and the sign kept on appearing. I then tried to boot into safe mode with no luck. When I startup with "option" and select the boot drive it also does not work. I then suspected fault with the SSD and got it replaced it with a brand new Samsung 850 Evo. Formatted and installed a clean version of OS X Sierra. This again didnt work. I then decided to do an internet recovery with a fresh install of OS X Mavericks which the laptop came out with. It did install successfully and I managed to setup the mac. However the moment I restart the mac, it does the same thing. However, I now sometimes get it to startup and then when I had the chance immediately upgraded to the newest OS X Sierra. It worked, but the graphics was extremely "choppy". So I restarted again, and there was the sign again. I cannot boot into safe mode, I can only boot into internet recovery.

Other options I explored was to

• disconnect the secondary drive and try to startup. Didnt worked first time, thereafter never again.
• Checked the SSD cable, and disconnected the battery and connected again.
• I have reset the PRAM and SMC.

I have tried to install a normal HDD again, and it works perfectly with it. However the purpose of buying an expensive SSD is to be able to use it and get my speed increased. Which worked for a long period of time with the previous SSD.

So have now run a diagnostic test, and the results shows no hardware faults. I am currently running an extended diagnostic test and will post the results here as soon as it finishes.

The only other fault that I have picked up which started showing up about two months ago was that the battery had shown a message, saying "Service battery". I cannot however see how this could be causing this problem, but if its possible, please explain to me. I have exhausted all of the possible solutions I could find online and now need some advice on this.

Is there anyone who might be able to assist?

Thank you in advance!

UPDATE: The extended diagnostic test revealed no fault with any hardware components.

Message was edited by: XFCVX

Hi,

It's obviously hardware related. The first thing I'd do is reinstall the original RAM and see if that makes any difference.

Next, I'd make sure the EVO works in an external enclosure so you're able to boot/run from it without issue.

Plenty of people have posted here about EVOs working for them in an external enclosure, but not when installed internally, for some odd reason. Others have no issues with EVOs. Some have found success with replacing the HD cable, even when it works fine with a regular/spinning HD. I supposed it's possible the extra data path needs of the SSD outdo what's available on the "old" HD cable. I don't know, I'm just repeating what has been reported here before. In any case, I think the simplest/cheapest thing to do is replace the cable with a new one, which is what I'd do.

最後更新：2017-08-18 01:11:46

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