Dont know when this started but when i am in a file collection and want to navigate to any (i think the problem is connected to pyhsical) drive via drivebuttons, the tab is showing "reading folder" until inifinity. I have to navigate the tab to "this pc" to be able to navigate further. Please let me know which information i can provide to you for further investigation.
If you have any script add-ins installed, try removing them. Those are the most likely cause.
If you still see the problem after that, please send us some process snapshots made while the problem is happening: Manually generating process snapshots