Excel Autofill ("drag'n'fill") suddenly not working

Question

Not working: Enable fill handle and cell drag-and-drop option despite setting
"File, Options, Advanced, Editing options, Enable fill handle and cell drag-and-drop option"

= Checked (active)

I need to find out why autofill (previously, yesterday? working!) with "drag'n'fill" no longer works for me. ACTION PERFORMED:
I normally fill in the first two or three cells so I can "drag'n'fill" the rest of column: ='[SomeFile.xlsx]DataTab'!A1 ='[SomeFile.xlsx]DataTab'!A2 ='[SomeFile.xlsx]DataTab'!A3

NOTICE (!): This "drag'n'fill" operation points to another, separate (network) file.

NEXT: I then grab the "cell-handle" to "drag'n'fill" down for 51 more rows down) ...but now that action just repeats content in these same three "over and over:"

PROBLEM:
Enable fill handle and cell drag-and-drop option"
= Checked/Active) ...but not working!

-------< EDIT: Elaborated more.

Answer 1

Solved: Rebooting - and properly initiating OneDrive. Because problem arose after booting from 'Hibernation.'