Author Topic: My 2015 iMac freezes on startup.  (Read 1140 times)

My 2015 iMac freezes on startup.
« on: 10 June, 2019, 02:02:09 pm »
As above.
This has happened twice in the last couple of days.
The thermometer bar progresses so far, and then appears to freeze or, at best, become glacially slow.
My solution has been to force it to quit, using the button round the back, and then to re-start it - and both times it has been fine.
Any ideas as to why or, more importantly, what I can do to address this?

TIA

Re: My 2015 iMac freezes on startup.
« Reply #1 on: 10 June, 2019, 02:04:32 pm »
Have you tried resetting the nvram etc?

Re: My 2015 iMac freezes on startup.
« Reply #2 on: 10 June, 2019, 02:15:07 pm »
Have you tried resetting the nvram etc?
PRAM I understand.
nvram - not so much.

Re: My 2015 iMac freezes on startup.
« Reply #3 on: 10 June, 2019, 02:18:09 pm »
You can try starting in “verbose mode” (google instructions) which will show you a load of output as it starts up which might diagnose where the fault is.

Does it have a mechanical hard disk? Does it freeze or stutter other times? If the answer is yes, changers are your drive is dying and you should take backups ASAP.

Re: My 2015 iMac freezes on startup.
« Reply #4 on: 10 June, 2019, 02:30:39 pm »
PRAM / nvram  appear to be similar/the same  - I've just re-set those - let's see how that goes.
Spinny HD, one of the last, not ideal for the current OS - my 2012 iMac actually starts up quicker on an aged OS.
No problems with the 2015 one running, once it is running.
Time machine backs up to an external drive at all times.

Jaded

  • The Codfather
  • Formerly known as Jaded
Re: My 2015 iMac freezes on startup.
« Reply #5 on: 10 June, 2019, 02:35:29 pm »
Try starting in Sungle User and doing a FSCK (hold down cmd and s at startup until white text runs up your screen - the things to type are at the bottom of the white text, fsck and when it has finished and said your disk was unmodified (or similar) then do the mount one, then type exit and return. it should boot normally.

Also, try downloading and applying the Combo updater for your machine. Apple menu - about this Mac, then check the version number and  then google combo updater 10.xx.xx as shown in that dialog box. Apply that. Then report back if no change!
It is simpler than it looks.

Kim

  • Timelord
    • Fediverse
Re: My 2015 iMac freezes on startup.
« Reply #6 on: 10 June, 2019, 02:45:07 pm »
Is this the generation of iMac that's prone to graphic card problems?

*defers to fruit-jibblers*

ian

Re: My 2015 iMac freezes on startup.
« Reply #7 on: 10 June, 2019, 04:26:04 pm »
It may also be some third party crap trying to start – well-behaved stuff goes under the login items preference and can be easily deactivated. It's generally not MacOS itself that hangs.

As mentioned verbose mode (boot with cmd-V pressed) will likely offer clues as to where it's hanging.

It's probably also worth unplugging any external hardware and checking everything is up-to-date.

Jaded

  • The Codfather
  • Formerly known as Jaded
Re: My 2015 iMac freezes on startup.
« Reply #8 on: 10 June, 2019, 05:50:23 pm »
Another thing to try is a Safe Boot (can’t remember the key press for that) which can sort out some software gremlins.

Basically, it is either going to be software, or hardware. Software can be dealt with, hardware not so much...

I’d advise checking the various software checks etc. first.
It is simpler than it looks.