My Mac turns on and then shuts down after a few seconds

Question

Hello everyone,

I have the same problem as someone named @nnie, namely that my Mac starts up, begins to load, and then shuts down at 30% of the loading bar.
I did manage to start it in Recovery mode and attempted a disk repair, but the repair tool tells me that the volume is in good condition. Yet, when I restart it, the same problem occurs.
It should be noted that my computer took a little tumble on the linoleum, but it had restarted normally afterwards for 2 weeks.
I have a Time Machine backup, and I would also like to know what data is backed up by TM. Will I recover my Word documents, my music, my photos, or just my settings?

Thank you for your response; I've heard great things about you, the "fine team"!

@nnie · Accepted Answer

Hi, it's me, the one called @nnie ;-)

Since you found my post, did you take the time to read it and have you tried out any of the solutions provided in it?

If so, which ones?
Is your Time Machine drive connected all the time?
If yes, then your backup is up to date, which is already VERY good!
All your data is on it, not just your config.

In that case, you can try restoring from TM.

I just hope you don't have as much trouble as I do, but since the Utility tells you that the disk is in good condition, that's pretty encouraging. ;-)

--
Please be patient: I have a 10-hour time difference...

*_Francis_* · Answer

Hello

The source of all the problems that @nnie had from the beginning was due to a defective RAM stick. (She had other serious issues before her Mac shut down by itself). She tested each stick and identified the defective one, then she was able to fix her problems.

Your Mac has fallen... which can happen in such cases, it's not necessarily a broken memory stick, but it could be its movement in its slot. It may no longer be properly clicked into its socket.

The Mac could also have experienced a malfunction of its management unit during the impact.

So you should start by:
- performing a reset of this management unit:
https://support.apple.com/fr-fr/HT201295

Then do:
- a memory test with Rember
http://www.kelleycomputing.net/rember/

A Time Machine backup can restore everything that has not been deliberately excluded from the TM backup.

Sincerely

--
To get an appropriate response, always provide your exact system configuration.
Have a nice day :-) - Francis

*_Francis_* · Answer

The indicated technique for resetting the SMC for a recent MacBook Pro:

Note: the laptops with a battery that you cannot remove yourself are the MacBook Pro (early 2009) and later models, all models of MacBook Air, and the MacBook (late 2009).
Shut down the computer.
Plug the MagSafe power adapter into a power source and connect it to the Mac if it is not already done.
On the built-in keyboard, press and hold the Shift + Ctrl + Option (left) keys and the power button simultaneously.
Release all the keys and the power button at the same time.
Press the power button to turn on the computer. 
Note: the state of the MagSafe power adapter light may change or the light may temporarily turn off when you reset the SMC.

The Option key is not the cmd key, but the alt key, the one with a sign resembling a switch.

The AHT test is long, which is normal. The longest phases are the memory and graphics card tests.

--
To get an appropriate response, always provide your exact system configuration.
Have a great day :-) - Francis

Hugledou · Answer

Well, I took a little tour of the solutions you suggested:
the SMC reset doesn't work, I plug it into a charging cable, follow the instructions, nothing happens, and when I restart it by pressing the power button, it starts in normal mode. And crashes.

In fact, a few days before my Mac died, I checked the remaining memory and I had 2/3 left, and now strangely it says I only have 19 MB of memory left, TM is only activated when my hard drive is connected, so I don't think that's the reason.

I'm seriously starting to think that the crashing issue is due to a hard drive failure, but when I check with Disk Utility, it says the volume is fine.

I dismantled the Mac and removed and reinserted the memory stick, but nothing changes.

I could try restoring from TM, but if the issue is hardware-related, that would be pointless.
Should I see an expert, or go directly to Apple so they can do a complete analysis of the computer?

Is there a way to transfer my data to an external hard drive to free up some space to at least download Rember?
Thanks again for your responses.

*_Francis_* · Answer

If the SMC reset manipulation is done correctly, it SHOULD work.

TM Machine activated only when the disk is connected??? There are no settings that allow TM to automatically deactivate in the absence of a disk or automatically reactivate.... do you take the time to manually disable and re-enable TM every time you connect or disconnect the external disk? Isn't it simpler to just click "Back Up Now"?

What you are calling memory is indeed the remaining storage capacity on the hard drive? If there really is only 19 MB left, there is a real problem.

I will test a deletion method by booting from the recovery partition, and I’ll get back to you...

EDIT: I can't do it right away, the Mac is finishing a task, but after the meal, it should be fine...

To get an appropriate response, always provide your exact system configuration.
Have a good day :-) - Francis

Hugledou · Answer

Yet I do everything correctly, I turn off the computer, I plug in the power cable, I simultaneously press Shift, Ctrl, and Alt, nothing happens, I restart the computer and it's as usual.

I don't remember exactly what settings I had applied to TM, but when there is no hard drive, nothing happens, no little needle at the top. And yet I do have backups on my external hard drive.
And the computer would have been overloaded for a while if that were the case, but it only became overloaded since it stopped starting.

Yes, when I start in recovery mode, and go to Disk Utility and select the hard drive, the information tells me that there are only 19 MB left. And if I run a repair, there are no bytes left.

Thank you very much for your help.

*_Francis_* · Answer

I press Shift, Ctrl, and Alt simultaneously,

And the power button?
And it's the left Alt key, right?

... I haven't been able to test a method for deleting a folder from a startup from the recovery partition yet, still working on the Mac... but I will do it...

--
To get an appropriate response, always indicate your exact system configuration.
Have a nice day :-) - Francis

Hugledou · Answer

Yes, also the power button, excuse me, yes it's indeed the button on the left.

My problem presents exactly the same symptoms as @nnie's Mac, apart from the fact that the hard drive says it is in good condition and that the utility works.
Don't you advise me like @nnie to store as much information as possible via target mode, then reinstall Yosemite?

*_Francis_* · Answer

Normally, if the SMC reset is done correctly, there are no particular signs upon restart. But when you press these 4 keys and release them at the same time, the Mac does not start until you press the power button again. So, maybe you did succeed in the reset. Except that sometimes Apple is overly optimistic when it says to simply press these 4 keys at once. You need to press those 4 keys and hold them down for several seconds before releasing them.

It's just like the PRAM reset (which also needs to be done), Apple says to start the Mac with those 4 keys pressed: alt - cmd - P - R, then wait until you've heard the startup "gong" twice, but in reality, it's better to let 3 or even 4 startup gongs pass before releasing those keys.

Annie's Mac had a defective RAM stick. This was verified both by TechTool and by Rember. This faulty RAM stick had previously caused corruption in several of her system files and her TM directory. Only after she removed her faulty memory stick could she get her Mac back to normal with the various resets and cleaning using Onyx. However, she had "benefited", if you can call it that, from a few moments when the Mac ran autonomously to perform these operations.

In the present case, the Mac refuses.

That said, if you have what it takes to run this Mac in target mode, it's very simple. Before considering a reinstallation, you should simply try to delete unnecessary items on this Mac.
You just need to connect this Mac to another via a Firewire cable and start it with the T key pressed. The Mac will then appear on the other Mac as a simple external disk, on which you can then do everything. Delete, repair...

Note that under Yosemite, you can reinstall OS X over the old system without data loss, but if there is no space available, this will not be possible. You must first delete items.

For Time Machine, the icon in the menu bar is only present if you have checked the appropriate box in its preferences. In other words, Time Machine can be continuously enabled even without the icon in the menu bar, and thus make backups in a buffer zone of the hard drive, filling it up. When the Mac is started in target mode, you can delete these provisional backups. I will look for the exact location of these provisional backups...

Hugledou · Answer

Good evening everyone and thank you for your responses!

This afternoon I called an Apple representative (and you were very helpful with that because you saved me from doing the basic troubleshooting like Recovery, SMC which turned out to be fine), we attempted to reinstall macOS but without success, so I’m going to use an external hard drive to transfer Yosemite to it, then format everything. I prefer to solve the problem the hard way rather than tear my hair out trying to figure out its origin, which I feel I'll never find since everything seemed to be against me.

Regarding the memory, strangely when I tried to install YO, I still had about two-thirds of my memory left. I think it's due to a silly glitch in recovery mode.

I’ll keep you updated for more info! Thanks again for everything!

--

My Mac turns on and then shuts down after a few seconds

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