Boot up issue with gray screen on iMac

John here again: :-)

Just a quick update which may help in figuring out what is wrong: I have rebooted into safe mode, after the reinstall of the OS failed to boot up properly - grey screen again.

However, as I have a home network, I've just found that I can still connect over the network with my MacBook Pro to the iMac, see all my user files on the iMac, and even copy them across to the MacBook Pro with no issues.

Everything on the iMac is backed up via Time Machine to a Western Digital 3Tb Firewire HD.

I also have uncompressed 'straight' manual copies of my music, movies, documents folders etc, to an older Time Capsule, which is currently acting as a wireless bridge to my ethernet based network, and to provide additional backup for those critical files - my music for instance is ripped 350 odd CD's, all legally purchased, in ALAC on iTunes on the iMac - which represents a couple of months work...lol... no way do I want to lose that!

So I'm at a bit of a loss. Disk utility is reporting no issues with the drive... I can boot up in safe mode and recovery mode, but normal 'mode' ... I still get the chime, apple logo with grey screen and progress bar, and then switches to just a grey screen instead of the login page.

HELP!

My beloved Einstein has had a hiccup!

All comments appreciated, and thank you again - hope this extra info helps

Kind regards

John... :-)

Hi BleverCastard

Many thanks for your input.

More or less - when I got a black screen this afternoon, I did a force shutdown, and then turned everything off, and rebooted the modem/router, the time capsule which is acting as a wireless bridge, my two airport expresses (to extend the WiFi network) and lastly the iMac.

I didn't pull the power cord on the iMac, but even though the Belkin surge board to which it is attached has a single pole power switch to the best of my knowledge, it should do the same thing - i.e. effectively turning it off at the wall. Well, I think so - of course I could be wrong!

Unfortunately I don't have a spare HD to install OSX upon to see if it will boot up from that - at the moment at least. I'm thinking of perhaps getting an external 2 or 3TB HD in short order, to make another copy of critical files, music etc, whilst I can - I can't directly access the time machine backups on the WD HD, as there's not enough space on the MacBook Pro to accommodate that - I'll leave it/save it to do a restore to a new or repaired iMac if it comes to that. I do have manual copies of critical files on the older Time capsule, which, being old, (and the power supplies in them were reputed to be flakey) I don't trust it enough under the circumstances to have it as the only manual backup of those files.

So until I can get another external HD, I'm a little stuck to try installing OSX on it and seeing if it will work.

I am however, a little lost as to why I can boot into recovery mode, safe mode, and all seems well - disk utility reports the drive is OK, and yet, it won't boot up... quite the mystery to me at least!

Kind regards

John... :-)

Ugh, I don't fully grasped the intricacies of this website - it wants to say the issue is fixed, - when it isn't!!

Grrr..

Kind regards

John...

Aah, well that rings a bell, as at the first pass of disk utility in safe mode it did report a problem with the partition that could cause boot up issues.

However, on subsequent passes, it reported all OK re the partition

It's a 2Tb HD in the iMac, mostly full - I have around 300GB left of free space which is probably a minimum for efficient operation of the HD/OS.

So I should create a new partition on the remaining 300GB of free space?

Thanks so much for the help!

Kind regards

John...

OK, machine is in safe mode; I just opened disk utility and ran it, not on the volume 'Macintosh HD" but the Hitachi HD, of which the volume Macintosh HD is a 'part' and it specifically reports " Problems were found with the partition map which might prevent booting"

I'm not completely au fait with partitioning - any thoughts here at all?

I'm starting to feel there might be hope... :-)

Kind regards

John...

OK, thanks Jordan

If I do this, will that erase the current partition, or 'volume' where my user files reside?

If the machine fails, I'd like to get those files off on to a separate HD if possible before 'the worst'...

Kind regards

John

OK, thank you Jordan - I assume it will overwrite the 'old' partition as regards the OS, but leave my user files intact?

I'll attempt this in the morning, as it's near 2am here, and there's not much left of my hair to pull out...lol.... time for a sleep methinks... :-)

Kind regards

John... :-)

Greetings All

Well, unfortunately Jordan, the 'worst' has happened and my beloved Einstein looks as if it has gone to the Apple retirement home in the cyber world..lol

I created a small partition on the Hitachi HD, and downloaded/installed OSX El-Capitan upon that partition - but no joy - it would not boot up past the chime, icon progress bar etc, just as in the MacIntosh HD partition. Oddly though, I could also boot up in safe mode and recovery mode in this new partition.

I'd actually made the new partition a little large, thus not leaving much space in the MacIntosh HD partition, so thought I'd remove it.

Despite that I checked very carefully what I was clicking and OK'ing, in front of my very eyes, the MacIntosh HD partition disappeared, leaving me with the 'new' one, and no change in boot up behaviour.

So then, I got out the original install DVD's - as mine is/was a late 2009 model, so does not have the firmware to allow internet recovery, and booted up from the DVD using 'c' command, and with disk utilities on the DVD, erased and reformatted the Hitachi HD - it auto partitions and creates a volume MacIntosh HD. Upon this fresh volume I installed OSX from the DVD, (being snow leopard) reasoning I could then install Lion with my install disk, which would give me the Apple store, and upgrade back to El Capitan, and restore all my date from my time capsule backup.

Nice idea - but... when it finished installing snow leopard and booted up, the screen was very garbled/fragmented and virtually unreadable.

I've tried rebooting several times, and it just gives me the chime, an icon and progress bar, goes to a blue, and then a gray screen with very fragmented graphics. And at that point I cannot hear any further HD activity.

I'm not an expert on the hardware side of it at all, but I would assume either a HD problem, OR electronic failure of another sort - most likely the logic board.

But I can't assume, as I'm not an expert - any comment on whether it would be worth while getting it looked at re possible repair, or should I do as a local apple retailer suggested and put it in the bin?

A pity to chuck it out if it could be economically repaired - it's an i7 quad core processor, 8gb ram etc with 2TB HD

Then again, it's six years old and things have undoubtedly moved on and one could be throwing good money at it only to have it fail somewhere else given it's age.

I'm sad...lol.... I really loved using it.

Still I have luckily used time machine to a WD firewire 3TB HD for backups, plus manual backups to an older Time Capsule drive, and my MacBook Pro to use, so it's not quite the disaster it could've been.

Many thanks for the help and advice - if you've any other comments, please feel free!

Kind regards

John... :-)