iMac running slow

Download and run Etrecheck. Be sure to give it Full Disk access before running.

Copy and paste the results into your reply. Etrecheck is a diagnostic tool that was developed by one of the most respected users here in the ASC and recommended by Apple Support  to provide a snapshot of the system and help identify the more obvious culprits that can adversely affect a Mac's performance.

Copy the report

and use the Additional Text button to paste the report in your reply.

Then we can evaluate the report to see if we can determine the cause of the problem.

Hi there!

If you think your Mac might have an issue, you can use this procedure to help gather information on your Mac which will help us troubleshoot your Mac’s problem.

To start, use this Apple Support article as a guide, Get system information about your Mac, and let us know what year your Mac is, the model, and what version of macOS you are currently using.

Next, please upload a screenshot of your Mac’s storage information. In the Finder, choose Go > Utilities, then double-click the Disk Utility icon. (Disk Utility is located in the /Applications/Utilities folder.) Alternatively, click Launchpad in the Dock, type Disk Utility in the search field, then click the Disk Utility icon. Once Disk Utility is open, take a screenshot of the information it automatically opens to, which will be your startup disk. Next, select View > Show All Devices in Disk Utility and select the top-level, non-indented, disk entry. In most cases, this name will be one of the following:

• APPLE HDD…
• APPLE SSD…
• Fusion Drive

Then, take a screenshot of the newly selected entry. Upload all screenshots here. 

Next, use Apple Diagnostics to test your Mac to help determine which hardware component might be at fault. When testing is complete, Apple Diagnostics shows the results, including one or more reference codes. Learn about Apple Diagnostics reference codes. 

Let us know which reference codes you receive.

Finally, let us know what antivirus, VPN, or cleaning software you have installed. 

Jack