hi my 2017 imac is unusabke after os monterey upgrade

Hi Timbo 1982.

Have you tried a startup in Safe-Mode?

If your problem is caused by a corrupted macOS cache setting after the upgrade to Monterey then a Safe-Mode restart may fix the problem.

Review this document for how to carry out a Safe-Mode boot:

https://support.apple.com/en-gb/HT201262

Note, there is no need to do anything in Safe-Mode other than allow the Mac to boot into Safe-Mode, which takes around ten minutes, wait for ten minutes for all background processes to complete then restart the Mac normally

As second issue that sometimes occurs after a macOS upgrade is that file ownership and permissions become corrupted, this can often be seen when right-clicking on any of your personal user files, selecting "Get Info" and at the bottom of the info window under "Sharing and Permissions" you see the spinning ball icon and the word "Searching".

If this issue is present on your Mac then restart in Recovery-Mode and carry out First Aid using disk utilities on each disk and partition on your system, in the sequence "Volumes" first, then "Containers" and finally "Disks".

Volumes are at the bottom of the tree view, Containers in the middle and Disks at the top.

Repeat First Aid on all the Disks and Partitions present.

For some partitions the First Aid icon at the top of the Disk Utilities window will be "greyed-out" this is normal, just apply First Aid to those disks and partitions where the First Aid icon is actively available.

See this document for instructions on how to use Disk Utilities and the First Aid tool:

https://support.apple.com/en-gb/HT210898

First Aid will repair file permission errors that may be causing the slow down of your Mac.

Lastly, you can just try a re-install of the macOS Monterey while keeping your data and apps intact, rather than carrying out a disk-wipe and a full "clean-install".

It is advisable to have a Time Machine backup of your Mac before carrying out a macOS reinstall just in case anything goes wrong during the re-installation of the macOS and your data or apps are damaged, if this occurs a current Time Machine backup can be used to just restore your data and apps only onto an otherwise wiped and clean-install of the macOS.

You will find it simpler to create a dedicated Time Machine backup to your external drive rather than manually copying your files over one-by-one since the Time Machine backup will have a snap-shot of all your files and apps and your current data can be fully restored on to a clean macOS system after a wipe and rebuild if necessary (although personally I like to keep both a Time Machine and a separate backup of important data on separate external disks).

This Apple document lists all the key combinations required to access the various start-up modes for a Mac:

https://support.apple.com/en-gb/HT201236

HTH

Will.

Hi Timbo 1982

Can't comment personally on the performance of the 2017 iMac that is listed against your profile when running Monterey but I have not seen any performance issues when upgrading my own 2017 iMac Pro from Catalina to Big Sur and then again from Big Sur to Monterey.

There are definitely some issues with Bluetooth support in Monterey, and the usual problems with apps that are no longer compatible after the upgrade, but absolute performance in regards time to boot and time to perform tasks in any app has not changed.

I re-read your opening post and see that you added RAM, was this before you upgraded or as a response to the slow performance?

I wonder if you did this before the upgrade and you might have the wrong specification, or faulty RAM modules added?

Have you loaded any third-party Anti-Virus apps or Clean-up apps, we know that these can be a big problem.

You could also try downloading and running the free-trial version of EtreCheck to carry out a system scan.

Give the program full disk access when asked and after the scan report is created click the button at the top of the report page to output the report then click the "< >" code insertion button at the bottom of your reply here and paste that report into a code box for the other forum experts here to check over, they may see something obvious that is causing the slow down.

You do not need to pay for the full version of Etrecheck, the basic report from of the trial version is sufficient for this forum.

EtreCheck is quite safe and does not reveal any private or personally identifiable information:

https://etrecheck.com

Will.

I've looked at more EtreCheck reports here than I care to think about and I am not seeing any big red flags either. Slow iMacs are usually due to slow mech hard drives or "split" Fusions drives. Your Fusion drive is properly configured and recognized, and performing at the top of its game.

Normally you install RAM modules in matching pairs—you have not— for best speed, but not doing so should not cause gross loss of performance. I assume you added the single 8GB module. If so, what make is it and what are the specs? Macs are picky about RAM. "Just any RAM" won't do.

Also verify that the computer is reporting the proper speed for the RAM. Do "About this Mac..." from your Apple menu to get this:

Then click the "System Report..." button to open the System Information app. Find "Memory" in the left-hand contents pane to see the RAM install and its speed. This is from my 2017 iMac 5K with 16GB RAM:

All modules should report 2400Mhz as in the image. If not, pull the 8GB module you bought and see if the computer feels faster.

That's all I have at the moment. I will be on the road for a day of two but I'll have my laptop; I'll try to check in to see what you found out.

Hi Timbo 1982

I read through all the Apple docs I could find regarding memory management on your 2017 iMac and can find nothing restrictive in the arrangement of your installed modules.

As Allan Jones notes, so far as the Apple docs are concerned it should not have an effect if the modules are different sizes on this model Mac, although I know this isn’t always the case with all computer hardware as mismatched size modules cause the memory manager to work in a non-interleaved and slower configuration.

Looking at your Etrecheck report I can see that you have a 4GB module alone in Bank 1, Channel A, and a 4GB plus 8GB module in Bank 2, Channel B, therefore the memory manager will be unable to use twin channel interleaved mode, if that is, twin channel interleaved mode is supported on Mac hardware for this model, I have no way of verifying this, it’s just a guess.

Besides Allan's suggestion to remove the 8GB module, which would leave the Mac a little short for good performance with Monterey, you could perhaps try moving either of the 4GB modules to the other vacant slot first. This would give you 8GB in both banks, two 4GB modules in one bank for 8GB total and the other single 8GB module in the second bank.

Memory slots 1&2 are bank 1 (or channel A), slots 3&4 are bank 2 (or channel B).

Probably won’t make any difference but worth a try anyway…

Will.

“how do I upload the etrecheck report?”

Hi Timbo 1982.

This linked page shows one way to attach the Etrecheck report using the “Additional Text Option”:

https://discussions.apple.com/docs/DOC-250000211

This linked page describes how to interpret the report:

https://discussions.apple.com/docs/DOC-6173

Will.

Hi Timbo 1982.

Nothing in the report shouts out a problem that I can spot but I will demur to others with more experience of this Mac model.

The CPU is only a 4 core and does not support hyper-threading so it would never be blisteringly fast but EtreCheck gives a good report for overall performance and there has not been a huge performance hit in upgrading from Catalina to Monterey that I am aware of.

Your plan to carry out complete wipe and clean-install is the logical next step after backing up your data and apps.

Your internal drive is a Fusion Drive, if I am reading the report correctly, if so, make a note of this Apple document, you may need it if the Fusion Drive “splits” into separate Flash and conventional hard drive after you wipe it pre rebuild.

https://support.apple.com/en-us/HT207584

Sorry I could not help you resolve the problem this time, hopefully one of the more experienced forum users will have something more substantial to offer you.

Will.