My vintage iMac suddenly began running quite slowly, complete with spinning beachball, as though some app is hogging operational memory. Where do I begin looking for the culprit?

Hi there!

I believe you should create an EtreCheck report. EtreCheck is a simple, helpful utility to diagnose and identify both software and select hardware issues.

If your Mac is experiencing an issue, such as poor performance or running slowly, kernel panics, apps freezing or quitting unexpectedly, storage issues, and many more, generating an EtreCheck report is a great place to start for troubleshooting issues with your Mac while getting help at Apple Support Community. EtreCheck was developed by a highly respected member of these very Apple Support Community forums, and it is trusted by many users.

Downloading

To get started, download EtreCheck:

https://etrecheck.com/en/welcome.html

Click “download” on the site. The app will be downloaded to your Mac to your downloads location, which is the “Downloads” folder by default. This can be accessed by going to the Finder > Go (in the top menu bar) > Downloads.

Open the app, and generate a report

Open the downloaded application, and follow the initial steps to open the app. Choose a problem in the drop-down menu, and click Start. Creating a report typically takes 2-4 minutes on a healthy Mac.

View your report, and upload a copy to Apple Support Community

Once you have your report generated, you can upload it to Apple Support Community for us to review and provide suggestions. Please refer to this document with instructions for uploading your report and using the “Additional Text” function of Apple Support Community:

How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community.

If you need help in the meantime, please let us know!

Jack

Unless you are running macOS 10.13+, then I don't think EtreCheck will work anymore with older versions of macOS.

For an older machine, a failing hard drive is a very real possibility or some third party software interfering with the normal operation of macOS. Typical culprits are anti-virus apps, cleaning/optimizer apps, and third party security software....none of which are needed on a Mac. If you have any of these types of apps installed, uninstall them by following the developer's instructions.

You can try running the Apple Diagnostics (or the Apple Hardware Test for really old Macs) to see if any hardware issues are detected. Unfortunately the diagnostics don't detect most drive failures.

FYI, it really helps to post the exact model of the Mac and version of macOS. You can get this information by clicking the Apple menu and selecting "About This Mac". Or if the Mac is not functional, then enter the system serial number here to get the exact model:

Find the serial number of your Apple product - Apple Support

In the applications folder there is an application called Activity Monitor. I use that to help me see what is sucking up my computer’s performance. You can see if there are big drains on memory or other processes.

The other thing is that sometimes there isn’t enough space on the hard drive for the computer to work. It needs space to write some of its temporary processes. Check your hard drive.

"...EtreCheck revealed an executable app ..."

The report contains tech details that may not mean much to you but can speaks volumes to those of us who have reviews thousands of them. It is designed NOT to reveal any personal or security information.

Please post the report; this how it was intended to be used. See the "How to..." link in Jack's post for how to post a long report in these forums.