Is File Explorer the same?
What's the full Event Viewer message? It would not usually report errors about the folder itself, so it's probably telling you something else is wrong.
Have you tried disabling your antivirus? That's often the cause of strange delays when double-clicking things.
If it's a spinning disk, could it have spun down since you last accessed it? Spin-up takes a few seconds.
Have you tried everything in this FAQ? Crash, exit or high CPU when viewing certain directories