Windows 10's File Explorer very slow with "working on it"

In the trace I see several activities of the MsMpEng.exe - Windows Defender (Build in AV suite in Windows). I also had several performance issues with it and always replace it with a 3rd party tool. Also do this and get rid of the Defender and it will make Explorer much faster.

I have found the solution is Reset Folders and apply across all your folders here:

It might help to reset the windows view to the default settings across all your folders. If your current view (basically what columns are displayed and how the icons look in each explorer window) requires that each file be opened to access certain information, it will definitely slow it down.

It's an easy fix to apply that default view across all your folders at once. This means that all your folders will have the view settings of a new installation of Windows 10.

To reset your current file explorer view to default, search for "Folder Options" at the start gem, select "Change search options for files and folders" (it's a control panel widget), and a "Folder Options" dialog will appear. Select the "View" tab, and you'll see "Folder Views" at the top. Click on the "Reset Folders" button and allow it to apply across all your folders. Then your view will be reset to default across all of your folders. After applying this, all your folders will appear similarly when you open them. You may then find that the directories open again with speed. If you make a change (such as adding a column to show bit rates), and it slows it down, you'll know why.

Why does this work faster? Because in the default view, windows doesn't need to open each and every file n the directory to pull up the requested info to show in the view, so it's much faster.

credits for: BigJohnnyO

A lot of reasonable solutions for File Explorer being slow can be found here: https://social.technet.microsoft.com/Forums/en-US/26147306-64c5-466d-a211-5a6a5f012575/why-is-windows-10-file-explorer-is-unaccepably-slow?forum=win10itproapps

I had very similar problem where besides very slow opening of File Explorer in Quick Access view, I had hang-ups when creating new folders, renaming folders and deleting folders.

With the help of the good people contributing to the above TechNet post I was able to resolve my problems. The biggest problem for me was that I had two folders on remote server pinned to the Quick Access list. The remote server is not always available and when it is, it is slow - in any case this caused File Explorer to choke for up to 30 seconds from time to time. Thanks to user Jeltz191, I unpinned the offending folders from Quick Access and the problems are gone now!

Some other mentioned remedies, such as not adding recently accessed folders to Quick Access and setting File Explorer to start in This PC rather than Quick Access, are reasonable settings anyway.

The suggestions to run sfc and DISM did not help me.

I am glad I did not have to enable Cortana, as was also suggested!