The general rule is: If you see a pin, you can unpin it. That rule fails if you try to Unpin Quick Access Folder in Windows 10. Commonly used folders should be pinned to the Quick Access area. Right click on any folder and choose Pin To Quick Access. Now you can go to the folder in just one click.
Unpin Quick Access Folder
In case you want to Unpin Quick Access Folder, you will want to click on the pin to unpin it. Unfortunately, that does not work. You must right click on the pinned item and choose Unpin From Quick Access option.
Drag drop also works for pinning folders. Drag the folder and drop it IN BETWEEN existing Quick Access Items. Be very careful while doing it. If you drag drop a folder on another folder, the entire folder will be MOVED or COPIED. Undo works in case you make a mistake. The cursor should look like this to PIN it rather than move it:
Use Quick Access area to speed up navigation to commonly used folders. If you are working on a project, add those folders as well. After the project is complete, remember to remove the related folders from Quick Access. Although Quick Access has no limit on entries, if you need to waste time to look for a Quick Access entry in a long list, it is not longer quick!