Ah, ok. So, when you added the 5th drive, did you swap out the 4-port 2.0 USB hub for the 7-port 3.0 USB hub? And have you tested the functionality of the drive with the Oppo using drive 5 in place of any of 1-4? It might be the presence of the 5th drive, or it might be the 5th drive itself.
If you swap a drive out using the old hub and everything works, then the problem is the larger hub hub. If it doesn't, the problem is the drive.
Thanks for all the help, from all replies. I'm going to have to chalk this one up as some kind of a gremlin.
Just to be clear I now have a total of 3 separate unrelated issues with my WD drives or the Oppo.
So the 1st is the hiccups from adding a 5th drive, which was months ago and the fix has been to only use 4. No matter how I connected the 5th drive either the 7 port hum or the 4 port and the front usb input it hiccuped here and there. You could almost live with it. One thing I never tried was 5 drives and no usb wifi doggle .
Then last week what turns out to be from the one drive it started stuttering. Totally unwatchable. Mind you all the original discs play fine, its my movie only and or music backups.
I had a spare drive and I copied the contents of the one that is stuttering and it seems to play fine. So I checked the one that was stuttering and now it plays fine. So who knows. It seems to be intermittent.
My 3rd problem is with the new drive which seems to work fine except that when I plug it into the computer I have to go to Disk Management to assign a letter to it, every time I plug it in or reboot the computer.
So my plan is to confirm that that the file are intact on the new drive. Then do through reformat copy all the data back to the old drive (not under warranty) If all seems to work correctly do the same reformat to the new drive which is under warranty and I opened a case file today.