Is it possible to downgrade the operating system?

iMac (Retina 4K, 21.5-inch, 2017)

Processor: 3 GHz Quad-Core Intel Core i5

Memory: 8 GB 2400 MHz DDR4

Graphics: Radeon Pro 555 2 GB

@jeanne81094 - What is the drive?

Sorry, just not sure what the drive is.

I think I found it, SSD.

@jeanne81094 - OK, that’s good! So that then gets into the size of the drive and how much free space it has. Often times the drive is so full it struggles! As most SSD’s tend to be a bit small for most folks.

We will need to create an external bootable OS installer drive so we can run Disk Utilities to clean things up. Do you have access to a 32GB USB thumb drive to setup and maybe a second Mac if this one is too slow.

You should still have the OS installer file on your system, go to the menu and select GO > Recents it should be near the top. Using Disk Utilities format your Thumb drive GUID Extended, then copy the installer file to it. Last step! Follow this guide to convert it into a bootable system Create a bootable installer for macOS. If you can’t find the OS installer file grab it from here How to download and install macOS I recommend you stick with Monterey for now, let’s see where we are once you boot up under the external drive accessing its copy of Disk Utilities. You can’t alter the internal drive if it’s the booting drive.