OS Update problem

[Calperon]

I have a 2017 iMac 27in with 16 GB of RAM. It has from new frequently displayed the spinning pin wheel despite Apple's hardware test showing no problems and I am careful not to leave unnecessary programmes running. Soon after purchase I became unable to use the RESTART or SHUT DOWN options so I made a clean update to High Sierra reinstating data by Time Machine. The update to High Sierra did not work correctly and I still cannot restart or close down using the on-screen options.
When I use either option the screen blanks and the cursor changes from my regular size to a mini one. I then need to close completely by holding down the power button. I can then only restart by again holding the power button and when I do so the progress bar stops near the end and I have to use the power button to close it again and then a second time to start it up. When I press POWER again, the progress bar starts at the point it left off. Today the second POWER restart took several minutes to complete.
I do need to update the OS despite that I will now lose Photoshop since the computer now slows dramatically during use and software that has always been flawless in use, sometimes freezes. The computer obviously needs the kiss of life.
Hopefully there is someone out there that knows a great deal more than I do about these things. It has been suggested to me that the system appears to be defaulting out of High Sierra altogether and into Linux, hence the change in cursor size.

 

[oldscribe]

Hi,

Sorry to hear you troubles. Open terminal and type the following command for a full list of any attached drives, one done close terminal then reopen it and type the following but replace “DISK” with whatever your drive is called.

diskutil unmountDisk force /Volumes/DISK

If your iMac shuts down great, leave for ten mins and reboot make a coffee then come back and try the shut down option from the Apple menu.

Let us know how things go.

 

[Calperon]

Unless I have failed to use a magic word it did not work as you can see from the screen copy below.
Any further suggestions? I am ready to lose Photoshop by updating to Catalina but since the last 2 OS updates did not work fully I am wary of that happening again.

Last login: Thu Feb 13 13:50:33 on ttys000
Mac-787b8abb819d:~ apple$ diskutil unmountDisk force /Volumes/DISK
Unmount failed for /Volumes/DISK
Mac-787b8abb819d:~ apple$

 

[cavebear2118]

Catalina is evil. I spent 3 months recovering from it and bought a "renewed" Maci Mini to solve the problem. And even now, they are trying to force me onto the lud every day.

 

[cavebear2118]

Catalina is evil. I spent 3 months recovering from it and bought a "renewed" Maci Mini to solve the problem. And even now, they are trying to force me onto the lud every day.

 

[Calperon]

Hi Oldscribe
I tried "diskutil list" in Terminal instead and it came up with the attached list of drives. The external drive will be my USB Time Machine. Does this help?

 

[oldscribe]

Hi,

You have recovery mode listed so I would try this first. If unsure have a look here.

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

Keep us posted.

 

[Calperon]

Apple Help suggested I reset the SMC by simply turning power on and off again , then I installed Catalina and hey ho, all the problems disappeared, though they did not do that when I reset the SMC I cannot guess. Thanks Guys.

 

[oldscribe]

Hi,


So pleased to hear this.