Slow iMac. EtreCheck report says......

Your Drive speed is dismal and dramatically slowing down everything you do on your Mac. On the software side the first thing I would look at is the Seagate ToolKit app. The app is named ToolKit and located in the Applications folder. If there is an uninstaller option in the app, you will want to run it to make sure any remnant files identified in the report are also removed from the Launch Folders.

On the Hardware side, the drive could be failing. The best tool to measure drive performance is DriveDX and also has a free download where no payment is required to view the report.

https://binaryfruit.com/drivedx

On a side note, you have an old unsigned version of Skype installed launching on startup. Uninstalling would be necessary and if used, then install the latest version after those files have been removed from your Launch folders. I don't believe the is the problem with the slowness, but something you would want to address after your problem is resolved.

Unfortunately the model you have is the next to the lowest performance iMac Apple sold at the time of purchase: 8 GB of RAM and a 5400 rpm fusion drive.

The drive has abysmal performance: Write speed: 59 MB/s and Read speed: 53 MB/s.

You have plenty of free space on the drive so it appears that it's failing. You could increase that speed by nearly 20x by getting an external SSD (OWC Envoy) and cloning your current boot drive to it with Carbon Copy Cloner. This user tip describes how: Using Carbon Copy Cloner to Make a Bootable Clone of Intel Mac. You can even get more speed with other OWC's Thunderbird external SSDs. Give their Customer Support a call and they can suggest the best match for your model iMac, workflow requirements and budget.

Mac Jim ID wrote:

On a side note, you have an old unsigned version of Skype installed launching on startup. Uninstalling would be necessary and if used, then install the latest version after those files have been removed from your Launch folders. I don't believe the is the problem with the slowness, but something you would want to address after your problem is resolved.

FYI, Skype no longer exists. Microsoft discontinued the service in May (2025) and it's no longer available. There are no updates to the app, it should just be removed.