Explorer.exe uses a lot of CPU on Terminal server 2019

Question

Hello there,

I was facing some trouble with CPU load on our test server, which is under winodws server 2019.

We use this server to test the devices that our company develops.

And after research I found that it's related to a lot of usb drives/devices (about 15) connected to this server.

During the test process every device can be reset many times and quite frequently.

All these devices are mounted to C:\MNT (This was made to hide devices on 'My Computer' home screen, but still be able to work with it's internal storage)

Looks like explorer.exe is trying to index or to do something else with these devices and consumes about 6% of CPU or 100% of one core. It happens even if you just open Explorer and keep it opened without traversing directories, or even if you open notepad.exe and keep the file->open window opened.

The 'procmon' shows that every explorer process is trying to write/query/queryinfo/close many and many-many directories.

And it does this endlessly, until the explorer window is not being closed.

I checked on the other systems and it does the same things but only once, and it took about 1-2sec tops, but if I connect any USB device (even headphones) it starts this check again.

We would have never noticed this if the server wasn't a terminal sever.

Due to about 6-10 users work on this server simultaneously and every user have his own explorer.exe opened it starts consuming 40%-60% of the CPU.

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At the beginning I thought that it caused by desktop visualization, so I've disabled all animations and transparency (don't understand why this could be needed on server system)

Then I was trying to disable indexing of files content.

Also, I added this config to the registry to avoid change notifications from remote smb shares.

Windows Registry Editor Version 5.00[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer]
"NoRemoteChangeNotify"=dword:00000001

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Does anybody know what options I have here? Is there some special registry key to stop this explorer behaviour?

Answer 1

Hi,

Thank you for posting your query.

Kindly follow the steps provided below to resolve your issue.

To prevent this issue, disable SMB directory change notifications by using the NoRemoteChangeNotify registry value. Do this on any systems that will be accessing the FileTable share through Windows Explorer.

To apply the setting to the user who is currently logged on, add the NoRemoteChangeNotify registry entry to the following registry key:

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer

To apply the setting to all users who log on to the computer, add the NoRemoteChangeNotify registry entry to the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer

Go to this link for your reference and other troubleshooting procedures https://learn.microsoft.com/en-us/troubleshoot/windows-server/shell-experience/increased-cpu-usage

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