Slow, very slow, external USB HDD

I have 3 external 3.5" HDDs, each mounted in their own drive caddy. They're all the same model of WD 2 Tbyte drives. I don't power them up every day but did do so today.

Copying files to 2 of them I found that 2 of them were running very slowly, looking at Task Manager's Performance tab the response times were varying between 1100ms, and over 8000ms!

Last time I used them, perhaps a week ago, they were fine.

Tried power cycling them, rebooting the PC, no difference. Did some Googling and then checked the Properties of the drives. Found that for those 2 drives the Policy^* option was set for Quick Removal. Changing to Better performance and rebooting, as was well.

^*Device Manager / Disc drives / [select drive] / right click drive / Properties / Policies

No idea how that setting got changed.

Thought I'd post this in case it may help someone else.