El Capitan to Sierra

[Arrandcb]

Ever since installing El Capitan my iMac has frozen when I try to shut down straight from the Apple menu; I have to go through the 'logout' protocol first - an irritant but nothing more. Now however I find I cannot complete the installation of Sierra as the machine will not 'restart' at the conclusion of the installation. All I get is a white cursor arrow on a black screen. I've tried 'logging out' before the automatic restart but all that happens is the machine restarts in El Capitan. Anyone else experiencing this? and if so what is the answer?

My iMac is a 2.5" late 2015 with 2.8Ghz processor and a Fusion Drive.

 

[honestone]

It would seem that there are software-related issues with your Fusion Drive, although I suspect it is the hard disk drive part of that setup. A couple of questions come to mind:

1. Have you been making backups to an external device?
2. Have you ever done any disk cleanup/maintenance/repairs to the internal drive? And if you used Disk Utility for any of that, did you do it in an "external" fashion?
3. How much free space is on the hard disk drive?
4. When did you install El Capitan? What were you using prior to El Capitan?
5. Do you have either MacKeeper or CleanMyMac on your machine? If you do, get rid of them immediately, as they do way more harm than good.
6. Did you insure to upgrade any third party software that you use prior to both of the OS upgrades?
7. If necessary, could you afford to lose everything on your internal drive, and starting fresh by Erasing and Formatting the drive, installing OS 10.12, and then using Migration Assistant to recover "stuff" from your external backup (assuming you have one)?

 

[Arrandcb]

Thanks for the response Honestone. Let me answer your questions in order;

1 Yes, via Time Machine to an external hard drive
2 No
3 In excess of 890 gig available
4 It was already on the iMac when I purchased it - Dec 2015
5 Yes - I have Clean my Mac - but I will bin it now
6 Yes - except Dragon Dictate
7 Yes, reluctantly - That was how I set up this machine. It replace a Time Machine backed up iMac that was written off by a lightning strike.

 

[honestone]

Thanks for the information.

So, apparently you have had this issue since you purchased the machine. Hence, it is/was necessary to fix this issue before upgrading to Sierra. That would have involved doing the disk cleanup/maintenance/repairs I mentioned above.

One other question I neglected to ask is have you upgraded El Capitan since you purchased your machine? I suspect at that time, it came with OS 10.11 or 10.11.1. Since then, there have been a few upgrades, with the latest version being 10.11.6 (came out about 6 to 8 weeks ago). Not sure if it would have helped much.

If I were you, I would first try and stabilize things before upgrading to OS 10.12. While you are doing that, and assuming things get back to normal, you should upgrade to OS 10.11.6. You can get the OS 10.11.6 Combo Updater from here:

https://support.apple.com/kb/DL1885?locale=en_US

But, first you'll need to boot to the (hidden) Recovery Partition, and run Disk Utility from there to do the disk "stuff" I mentioned above. This links describes how to boot to that partition, and what it contains:

https://support.apple.com/en-us/HT201314

There are also a couple of excellent freeware tools you can use as part of this effort.