Solved! Numerous persistent Windows Explorer processes (Windows 10)

[tcsenter]

I happen to check Task Manager for something on my Windows 10 Pro system, notice my memory (RAM) usage was kinda high given I had NO apps open - 5.3GB, normally should be around 3.5-ish GB for just the basics of Windows, device drivers and their required background utilities, etc. I use Firefox not Chrome and at any rate have turned off all those 'keep a gob of processes in memory for better performance' features in Edge. I check Processes and notice 20 ~ 30 different Windows Explorer (Microsoft) entries. Each grabbing several to several dozen MB. I ended/killed several of them, restarted Task Manager and notice memory usage declined to 4.9GB. I decided to just restart the system.

Upon system restart (and waiting about two minutes after desktop appears), memory usage was back to reasonable/expected 3.5GB. Even when composing this in a single Firefox window, memory usage is only 3.9GB. There is only one Windows Explorer process.

A couple hours prior, I was doing some duplicate file housekeeping, deleting some old stuff on a few different hard disks, both internal and USB connected, which involved opening Windows Explorer a number of times, comparing two different directories, closing the Windows, and doing it again for other volumes and directories. I can only guess that Windows did not 'release' those processes or handles into them? But the question is, why?

The windows were closed and the PC was idle for over an hour (sleep or hibernate are disabled) before I came back to it and notice this.

 

[Tech Junky]

W11 invoked tabs for explorer and normal use should only spawn one instance besides the one that make the desktop work. It's a bit odd to see residual explorer instances though. Might be related to the adware windows will be pushing if you don't have it blocked.

 

[tcsenter]

I think I found the problem. I was using Duplicate File Finder built into CCleaner (Piriform). In the list of duplicates presented, it offers the function to 'open file location' in Windows Explorer. It appears CCleaner uses some kind of file manager process that may not have been releasing the previously opened Explorer Windows.

 

[tcsenter]

Oh and to clarify, I know that CCleaner has the 'run in background' thing, 'Smart Clean', notifications, etc. I turn off ALL that stuff in advanced options, so that when I close CCleaner, all processes should close/terminate and nothing runs in the background. I did a test to reproduce the issue with CCleaner and the same thing happened.