Cannot copy-paste anything into my WD elements

WD External and Portable SSD External SSD for macOS
1

I have a WD elements portable hard drive.
I have OS X El Capitan 10.11.6
I have converted it to mac and it is connected to Time Machine.

My problem is when I try to drag-and-drop or copy-paste an item in to the external drive a pop-up window appears saying:
“Modifying “MacBook Pro” requires an administrator name and password.” and it tells me to click on “Authenticate” but when I do, a new pop-up window appears telling me:
“The operation can’t be completed because backup items can’t be modified”

Please help, what do I do?

2

Hello,

I found some information on the apple community about this error.

See if this helps
https://discussions.apple.com/thread/3283934?start=0

3

Thank you but I have already tried this and it does not change anything