my 2017 imac with 32GB RAM, 2TB Fusion drive 4.2 GHz Quad-Core Intel Core i7 has become very slow

This is abysmal:

Performance:

System Load: 1.95 (1 min ago) 2.29 (5 min ago) 2.07 (15 min ago)

Nominal I/O speed: 7.37 MB/s

File system: 20.52 seconds

Write speed: 47 MB/s ⚠️

Read speed: 151 MB/s ⚠️

I'm surprised the computer works at all. For a healthy Fusion drive with your drive specs, your Writes should be between 600-900MB/sec and your Reads up to 2000MB/sec. That's based on hundreds of Fusion Drive reports from EtreCheck that have been posted here.

We've seen plenty of evidence that CMM can slow storage speeds, but not as much yours. Yours is slower than many failing mechanical-only systems. I I am reading DriveX report correctly, I see a lot of 100% results and no failure flags. I confess to being under-skilled at reading DriveX results and must rely on someone more familiar with the utility.

This is a big clue to bad performance that support rkaufmann87's point:

Top Processes Snapshot by CPU:

Process (count) CPU (Source - Location)

WD Drive Agent 93.56 % (Western Digital Corporation Branded Products Group) ⚠️

com.apple.appkit.xpc.openAndSavePanelService (3) 56.95 % (Apple)

MTLCompilerService (32) 49.33 % (Apple)

Safari 41.77 % (Apple)

Mail 22.86 % (Apple)

To expand on rkaufmann87's excellent advice re removing drive software: WD's drive software has never worked well and, for me, caused stalls and overheating in both older PowerPC Macs and current Intel Macs. Uninstalling their apps and supporting files restored proper function for me. There should be an WD uninstaller file. Otherwise: https://support-en.wd.com/app/answers/detailweb/a_id/51137

Also Passport drives are very "entry-level" and not as robust as more expensive external solutions. They tend to get a little flakey with age. Disconnect the Passport, restart, and see if things speed up.

This could be caused by multiple issues, however considering the age of the computer I would first test the Fusion Drive. Please download the free version of DriveDX and run a test on your drive. If any errors appear that indicates the hard drive is failing and should be replaced. However if no errors appear (look very very carefully) then please move on to the following suggestion.

It will help us get a good idea of what is causing your problem if you provide a report of your system, that way we do not have to play 20 questions with you. The report we are requesting does NOT provide any personal information and is extremely safe to use. Please navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.

When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 

For instructions on how to download your EtreCheck report and attach it to your reply to this message please click How to use the Add Text Feature When Post… - Apple Community It is helpful to us if you download the report to your Desktop.

CMM is showing on your EtreCheck report. You likely did not follow the directions for uninstalling from the Developer. What I'd recommend is you download the free version of FindAnyFile and search for "Clean My Mac" and also, the developers name which is "MacPaw". IF you think you have removed all of CMM then run a fresh EtreCheck report and carefully review it for any evidence, if you find the name "Clean My Mac" or "MacPaw" then you have not removed it!!!!

I did not say your external SSDs or HD's are bad, I said the software you installed from them is not needed. What I mean is, for example if you bought a WD external drive (SSD or HD) and installed any WD apps then get rid of those apps and remember to empty the Trash!!!!!! Same thing for any manufacturers external SSD or HD.

Also, the DriveDX report only show information on the SSD portion of your Fusion Drive. I suspect it is the hard drive portion that may have a problem. PLEASE check that and look closely for errors. Please use the instructions in this user tip by Jack-19 How to use DriveDx - Apple Community

You are correct, the system does have problems. First is you installed Clean My Mac which at best is 100% worthless and at worst a major contributor to your problem. Most experienced users on these forums consider it malware. Mac OS does NOT benefit in any way by installing third party:

• Cleaning apps
• Antivirus apps
• Security apps
• VPN apps

Please locate CMM's uninstall instructions and then uninstall and restart in Safe Mode and then restart normally. In order to keep Mac OS running well, simply keep it up-to-date and restart the computer about 1x per week.

Next, it appears you installed software from third party HD's and SSDs that you have attached to your computer. This is also garbage software and should be uninstalled immediately.

Finally, you have disabled Time Machine and there is no evidence you backup your computer. This is shortsighted and a 100% guarantee you will lose data. Please fix that immediately

Finally, please post your DriveDX report I would like to review it. It is smart to always have multiple sets of eyes view reports as you can miss things that others catch.

If you cannot get the remaining CMM 5 files deleted then the last recourse is to do an erase (format your drive) and install. Remember an Erase and install means all and I mean all the data on the Fusion Drive will be removed. This means you will need to install Mac OS from the Recovery Partition and manually restore all of your apps and data. This is simply another example of the insidious damage CMM and other similar apps can do to a computer.

Prithvi wrote:

<DriveDX report of the Hard Dtive.log>

I have used the Find Any Files app and found about 83 file of Clean my Mac. I was able to delete about 78 of them however the other 5 are not deleted. It requires a Root Permission! I have tried that but was unable to delete them.

I shall run the Etrecheck again later and get back.

Thanks