Can you help me understand my Etrecheck report?

Your iMac appears to have shipped with Apple's Fusion (hybrid) drive, but the critical software connection between the two physical components of the drive—a 28GB NVME solid-date drive and a 7200 RPM SATA 6 mech hard drive—has been lost ,resulting in a "split" drive. And the speeds reported indicate that you are booting off your WD external SSD.

That Fusion configuration when working will deliver Write speeds of 600-900MB/sec and Reads of up to 2000MB/sec based on drive speed data I've collected. Your current speeds are here:

Performance:

System Load: 1.01 (1 min ago) 0.98 (5 min ago) 1.50 (15 min ago)

Nominal I/O usage: 0.46 MB/s

File system: 23.80 seconds

Write speed: 422 MB/s

Read speed: 427 MB/s

Those are the expected speeds when you boot from an external SATA 6G SSD in a USB3 enclosure, which is what you have. That also could explain the slowdown you describe. The external USB/SSD drive is slower the the original Fusion setup

The "split" likely resulted from this:

I have tried reinstalling the system, but that doesn't help.

Advice to reinstall the OS on a Fusion Drive system often creates issues. Apple's article is here:

How to fix a split Fusion Drive - Apple Support

You may have an old adware infection imported by Migration Assistant:

[Loaded] net.culater.SIMBL.Agent.plist (Not signed - installed 2012-05-30)

Executable: /Library/ScriptingAdditions/SIMBL.osax/Contents/Resources/SIMBL Agent.app/Contents/MacOS/SIMBL Agent

👉🏻 (note the install date: 2012!)

that is doing this:

Diagnostics Information (past 7-30 days):

2023-09-14 12:19:40 SIMBL Agent - Crash (191 times)

Executable: /Library/ScriptingAdditions/SIMBL.osax/Contents/Resources/SIMBL Agent.app

I've never seen that many crashes for one process in an EtreCheck report. When I was in law enforcement, we called that a "clue."

You have MalwareBytes; that should remove SIMBL processes.

Try removing the client-side VPN. They tend to cause more issues than they prevent.

Back to the etrecheck report...

Delete these files & restart...

~/Library/LaunchAgents/com.erikhinterbichler.HeraldLaunchAgent.plist

~/Library/LaunchAgents/com.snap.SnapCameraAutoLaunch.plist

~/Library/LaunchAgents/com.adobe.ARM.***.plist

/Library/LaunchDaemons/com.splashtop.streamer-srioframebuffer.plist

/Library/LaunchAgents/com.splashtop.streamer-for-user.plist

/Library/LaunchDaemons/com.splashtop.streamer-daemon.plist

~ tilde indicates your user library folder

Apple hid the Users' Library folders...

Method 1:

1 From the Finder, select the Go menu at top of the screen, and choose Go to Folder.

2 In the window that opens, enter ~/Library, and click Go.

Please determine if the same problems occur in "Safe Mode": Use safe mode on your Mac - Apple Support.

You can rule out software issues by running in Safe mode like John Galt suggests or running from a different clean install of MacOS.

But my suspicion is hardware, either your iMac's Power Supply is slowly going bad (there are a lot of replacements available at affordable prices, which could be a hint), OR which I suspect even more, one of your externally powered devices like external Hard Disks is causing the issue. I would try running without any externally powered devices connected for a while to see if that changes the behavior.

It appears you have a lot of external drives connected, and perhaps one of them contains your photo library?

Have you tried (after rebooting to Safe Mode, as suggested by John Galt) disconnected all external devices and see what happens to your Mac's performance?

f'sl wrote:

Is the photo library a known problem? Or having it externally? Thanks!

Typically, no, it's not an issue. But it could be if there are issues with the external drive, or if the library itself is somehow corrupted and needs to be rebuilt.

👍