This happened yesterday. Everything that had to do with windows explorer started freezing or super slow. Saving files, opening file explorer, everything. (not specifically my mycloud home drive)
Tried every method online, cleaning cashes, disabling explorer features, I was getting desperate. Nothing would work. Rebooting made the explorer work normally for a few minutes, then trying to open it gave me a white loading window.
Out of nowhere I decided to quit dropbox, nothing happened. Then I did the same for the WD Discovery app from the trey icon, and instantly explorer started working again with no issues at all and it opens normally in about 0.01 seconds.