Disabling auto-hiding of vertical scrollbar in Word 2013

There is a hack that stops the scrollbar from disappearing, though I'm not sure whether Microsoft considers it a bug or a feature:

1. Go into "VIEW | Read Mode".
2. Select "VIEW | Layout | Paper Layout".
3. Press Escape to get back into Print Layout, and then the scrollbar shouldn't disappear.

To do this more quickly, get used to typing:

1. Alt-W-F
2. Alt-W-L-P
3. Esc

Jez’s answer is good, but it is rather annoying that you have to do this every time you start Word, so I just made a macro (by recording the keystrokes) and then put the macro on the Home tab of the Ribbon.

Here's the macro:

Sub Fix_Scrollbar()
'
' Fix_Scrollbar Macro
'
'
    ActiveWindow.View.ReadingLayout = Not ActiveWindow.View.ReadingLayout
    Selection.EscapeKey
    If ActiveWindow.View.SplitSpecial = wdPaneNone Then
        ActiveWindow.ActivePane.View.Type = wdPrintView
    Else
        ActiveWindow.View.Type = wdPrintView
    End If
End Sub

So now it’s just one click when Word starts ...

It seems there it's no solution for your problem at the moment:

http://answers.microsoft.com/en-us/office/forum/office_2013_release-word/word-vertical-scrollbar-auto-hiding-in-print/2656ff19-ebc6-4f3f-8611-121bfd4072ab?page=1&tm=1434983755116

I disabled the animations (smooth movements) in all the Office 2013 and I have the same auto-hiding of the scrollbar you're refering.