Mac OS forum


Stop sign at boot!

At Christmas I updated my failing Mac mini original hard drive to a SSD, and upgraded to Yosemite at the same time. I used the Trim enabler app to enable TRIM and disable kept signing, this worked well. Sporadically since then on boot, the no entry sign will show for a few seconds, but will then disappear and the boot will continue as usual.
however, a few day ago, in an attempt to fix a much lesser issue of a mission control desktop being created every time I boot, I started the Mac in Safe Mode. This was fine, but when i then tried to restart in normal mode, the stop sign came, and stayed.

I Tried to follow Cindoris instructions on how to recover from this issue via Terminal commands in Recovery mode, but it would always get to the last command before it came up with an error message along the lines of something not being able to be found.

I Keep a Time Machine backup on constantly and following the issue, I went into recovery mode and recovered to an earlier, safe time.
On completion, when the Mac auto booted, the no go error sign came, but thankfully went.

I Then used the Trim enable app to turn on trim, which it said was off, and on the restart it does to disable kept signing, the error sign occurred!

Any help would be much appreciated!

Mac mini, OS X Yosemite (10.10)

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Two things to swap.

In reply to: Stop sign at boot!

I'd try a new SATA cable and another SSD.

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Thanks for the reply!

In reply to: Two things to swap.

Thanks for the reply Bob! May I ask, why do you think the hardware is the issue here? It is not like I tampered with it to cause the issue - I simply booted into Safe Mode, and on reboot after that, that is when the issue occurred.

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The story sounds hardwarish to me.

In reply to: Thanks for the reply!

Just an opinion along with thoughts about changing a cheap part first. Source? Lots of machines, too many incidents of iffy cables.

If it is software/OS, a reload would cure it.

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In reply to: The story sounds hardwarish to me.

Thanks Bob. I see your point, but wouldn't a dodgy cable mean I wouldn't be able to boot at all? I say this because I am in fact replying to you VIA the Mac in question. TRIM is currently disabled, although as long as I don't reboot, the Mac works fine. Now this of course if only a temporary solution, I DON'T want TRIM disabled medium-long term, and I DON'T want to leave my Mac on for longer than the short term. But surely this shows that there is no hardware fault?

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Here's why.

In reply to: Interesting...

When machines boot they don't automatically start at the highest SATA or other speeds. The boot process begins with lower setting and cranks it up later. Without diving into the OS and other code you can't be sure when this happens but booting can succeed and have failures later. There's also the issue of electrical noise in the system. It can be lower during boot and as more bits of the system switch on and up you get more noise and the odd failure. It can create a mystery to those new to computer designs.

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In reply to: Here's why.

Well after restarting my Mac after about a day, without doing anything - it seems to be working normally again! Still occasionally seeing the stop sign, but it always disappears after a few seconds like before. I reinstalled the OS anyway - although that doesn't seem to have changed much - and it feels like it might well be a hardware related issue due to the inconsistencies, maybe with the 3rd Party SATA cable connecting the 3rd Party SSD. Whatever the issue, I can only hope it doesn't appear again!

Thanks for all your help!

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