MacBook Pro 2012 Startup Glitch: reason unknown

rLo_101 wrote:

Laptop kept on restarting when I logged in, going back to the login window. I restored from Time Machine and now it does not recognise the login password. I don’t keep track of all my old passwords and I'm now locked out.

I used terminal, reset password in recovery mode. This tells me that the password reset is complete but there's no other instructions or field to change the password just an exit button.

Also tried to reinstall Catalina in recovery but got a hang with 3 minutes to go.

I think I’ve repaired a disk problem in Disk Utility, First Aid.

Would like to keep using it more offline.

hmmm...

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rLo_101 wrote:

I erased the disk to reset it to the original factory settings, eventually completing the download of Catalina in recovery mode on the 3rd attempt.

Now there's no lead to the Startup disk (Macintosh HD) it says: installer resources could not be found.

Diagnostics says there may be an issue with the memory module.

But Disk Utilities First Aid is all OK on all devices shown.

Holding down the Option key at startup shows a picture of the startup disk but again is not able to find it – or the resources.

https://discussions.apple.com/content/attachment/8106e73e-9760-431a-a2ed-35eafd17bc51

https://discussions.apple.com/content/attachment/7eb31346-635a-4ca8-a051-a3529e2e16aa

Disk Utility does not test memory.

I would try resetting the  System Management Controller  Reset the SMC of your Mac - Apple Support 

if no progress

Try resetting NVRAM/PRAM Reset NVRAM on your Mac - Apple Support

Hi there,

It seems like the formatting of your disk isn't compatible with the OS version you are using.

I once had the same issue on my 2017 iMac, and this helped:

1. Hold the power button for ~6 secs to shut down your Mac.
2. Wait a bit, then power your Mac by pressing the power button.
3. If your Mac shows up a spinning globe or just keep restarting, shut it down.
4. Wait a bit, then power up your Mac and immediately start holding ⌘R.
5. Shortly, your Mac will start up in Recovery mode.
6. In Recovery mode, select Disk Utility, then click Continue.
7. Select your main disk, and make sure that it is formatted with APFS (Apple File System).
8. If it is formatted with APFS, you can close Disk Utility.
   1. If it isn't formatted with APFS (Journaled HFS+, for example),
   2. Erase the disk with the regular APFS formatting (This will remove all data stored on your hard drive!)
   3. Wait to the disk to be erased. If the process keeps loading for a long time, start from the first step.
   4. Once the disk had been erased, you can close Disk Utility.

Now try reinstalling your OS in Recovery mode.

rLo_101 wrote:

[...]

Diagnostics says there may be an issue with the memory module. But Disk Utilities First Aid is all OK on all devices shown.

[...]

Yeah, FYI, Disk Utility works with and checks the storage devices; internal and external drives. This is the permanent residence of your programs and files even when the computer is turned off.

The memory modules that you refer to provide the temporary workspace in your computer that gives applications a place to store and access data on a short-term basis while the machine is turned on. Sometimes these modules can have problems that result in the symptoms your Mac is experiencing. Memory modules may be replaced in some computers, but not all.

Restart your Mac from startup options, and then start recovery mode (⌘R).

I now tried to cause your issue on my Mac, and the steps above resolved the problem.

Restart your Mac after each steps of the possible solution above, to see if reinstallation is needed or not.

(OS reinstallation might not be needed if your Mac restarts without error)

With the non-Retina models, the one memory slot is most likely the cause of the memory issue. The memory slot nearest the Bottom Case tends to develop cracked solder joints. My money is on a bad memory slot. Very rarely do I ever find the other memory slot nearest the keyboard fail or a memory stick failing.

If you only have the default 4GB (2x2GB) RAM configuration, then if you want to purchase memory I would only purchase a single 8GB module because the chances of that one memory slot being bad is extremely high. If I'm wrong, then you can re-purpose on of the original 2GB modules to have a total of 10GB of RAM which should be more than sufficient.

The other problem you may have if this is a non-Retina model is the internal hard drive failure and/or the failure of the internal hard drive SATA Flex Cable. The SATA Flex Cable has an extremely high rate of failure on the MBPro 13" (mid-2012) non-Retina model. Their are several possible symptoms associated with a bad flex cable. Installing macOS to an external USB3 drive is an easy way to bypass & even confirm an internal drive/cable failure.

Is it worth spending any money on this laptop? I'm not necessarily against it since it is the last upgradeable Apple laptop.

<< there may be problem with a memory module ...

if yours is not the Retina model, You can replace Both with two 8 GB modules for under US$30.