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.”