How do I uninstall macOS Ventura 13.7.5 on iMac 27" 5K?

seagreen939 wrote:

It really did not work well before this new update either. How would I find what this new OS replace?

If you can't tell me how to find the info, your comment is useless.

Sorry that I wasted your time when trying to help :-/ FWIW System Information > Software > Installations has a list of some past installs although that might not help much in the actual problem. You have not answered what kind of drive that Mac has -- a failing drive, a failed fusion drive or APFS on a HDD boot drive might cause these kinds of issues.

Downgrading from an OS requires fully erasing the drive and downloading and re-installing an earlier macOS version. It isn't for the faint of heart. It is generally considered the last resort after other troubleshooting steps have failed.

Have you restarted your Mac lately?

Rebooting is the best first step in troubleshooting.

If a simple reboot of your Mac doesn’t fix things, see if the problem still happens in safe mode.

How to use safe mode on your Mac - Apple Support 

Safe mode will often correct weird software behavior by forcing the OS to clear caches, do disk repair and other housekeeping and temporarily disables third-party mods.

Does the same problems happen while in Safe mode?

If not, this may be an indication that the problem is caused by some third-party software that you have installed.

You can exit safe mode by restarting your Mac normally, then reevaluate the problem.

Before you reinstall macOS, you must have a Time Machine or other backup of your files and data. Back up your Mac with Time Machine - Apple Support

To reinstall macOS, restart the computer in recovery mode. Guidance for the process can be found here:

How to reinstall macOS - Apple Support

seagreen939 wrote:

How would I find what this new OS replace?

If you can't tell me how to find the info, your comment is useless.

Your demand is not realistic.

Apple does not release detailed lists of every system file that changes from one version of macOS to the next. An installer that does an incremental update would need to have, or be able to compute, such a list. But my guess is that even developers working in macOS groups in Apple Engineering would not know the contents of the list or be able to produce them without spending a lot of time to research the matter. Even if you had the list, you would not be able to make much out of it unless you were a software developer AND had knowledge of and access to macOS source code. (Access, which, as a regular customer, you do not have.)

Here is what Apple has publicly disclosed about Sequoia updates.

What's new in the updates for macOS Sequoia - Apple Support

macOS Sequoia 15 Release Notes | Apple Developer Documentation

Safari Release Notes | Apple Developer Documentation

Apple security releases - Apple Support

seagreen939 wrote:

[...] How would I find what this new OS replace?

Info about files replaced with a new OS version is not available to us in the general population.

This is the closest I can get: What's new in the updates for macOS Ventura - Apple Support

A very common cause of Mac problems is the installation of third-party anti-virus app, along with clean-up, optimizing, security and VPN apps. If you are running any of these it is recommended that you disable and/or uninstall them and reevaluate the issue.

For more info, please see these support documents:

• Effective Defenses Against Malware - Apple Community

• Avoid phishing emails, fake 'virus' alerts…and other scams - Apple Support

seagreen939 wrote:

[...]

Why aren't there other tools to find the issue versus having to reinstall another faulty OS?

This did indeed happen with the prior OS, but the delay was not so severe that I wanted to punch the iMac. Which is why I don't really want to go through the difficulty of reinstalling.

There are other tools.

For example, this: please run an EtreCheck (free) evaluation of your Mac and post the generated report back here in a reply. EtreCheck is a safe and highly regarded utility from a trusted developer and respected ASC contributor. The diagnostic report will not include any personal info. It simply gathers specifics about hardware performance and installed software that might be in conflict with the OS.

Please navigate to EtreCheck.com to download the utility. Be sure to Allow Full Disk Access when you install the app. Once you’ve run the app and created your report please post it with your reply to this message. 

Please note you must upload the full report. To see how, please click >  How to use Add Text when posting… EtreCheck Report.

We’ll use your EtreCheck report to look for the things that may be causing your problem and advise how to correct them.

Can I drag the iMac to an Apple Store?

You can make a Genius Bar appointment for hardware/software service and support using this link: Contact Apple Support - Apple Support

If your iMac is super slow after upgrading to Ventura, you can try using Activity Monitor to see if any apps are using up too much of your computer’s resources. Also, use Disk Utility to check and fix any disk problems. If you want to uninstall Ventura, you’ll need to reinstall macOS. To do this, restart your iMac and hold Cmd + R to enter Recovery Mode, then choose "Reinstall macOS" and follow the steps to go back to the macOS version you had before.

What kind of internal drive does that Mac have? SSD, Fusion Drive, HDD? What macOS was used before upgrading to Ventura?

"Fusion" drive or SSD drive?

Perhaps the drive is failing.

You may want to check out if some of these reports match your experience:

https://duckduckgo.com/?q=imac+2017+fusion+drive+problem