Windows 10 Often Freezes When Saving or Opening Files

Ok so I found a solution from here:

Fix – Windows 10 Freeze Renaming – Saving Files and Folders

If you use lots of shared folders (NAS and network in general), Windows 10 quick access algorithm could create troubles.

Simply disable it to achieve again maximum response time from your system.

To change how Quick Access works, display the File Explorer ribbon in any folder, navigate to View, and then select Options and then Change folder and search options. The Folder Options window opens.

uncheck “Show frequently use folders in Quick access.”

uncheck “Show recently used folders in Quick access.”

press “Clear”

I made a GIF to show:

Make sure both boxes in Privacy are unticked.

I finally figured out that the culprit was hard drive spin-down.

For those interested, you can increase hard drive idle detection time to a very high value or to "0" (never) in your Power Settings.

This keeps the hard drive running and you will no longer experience issues with wait times on dialogue Open or Save boxes, although it does keep your hard drive always running.