Scroll Bars missing in Adobe Acrobat Reader

Scrollbars missing in Adobe Acrobat Reader (version XI version 11, Acrobat Reader DC).  Vertical scroll bar missing.

Problem:
Vertical scrollbars missing when viewing a multi-paged PDF file.

Reason:
Adobe is by default assuming you have a touch-device but I have no idea why Adobe would set this as a default.  Regardless of a touch-screen, a scroll-bar is useful on any device, no matter what method is used for scrolling.   


Quick Solution for current Document:

This change only affects the current viewed document.  See Permanent Solution, below, for a better method.

A.  Acrobat Version 11 and older:
      Within Reader, top-menu, choose "View", Show-Hide,
      Uncheck [ ] Touch Mode

      If the top-menu is not visible, press F9.

      If the "Touch Mode" option is not available, especially in newer version of
      Reader (DC), see the preference setting, below.


Permanent Solution - All Documents, All Versions of Acrobat Reader:

1.  Within Acrobat Reader, select Top-menu "Edit", Preferences
     If the top-menu is not visible, press F9.

2.  In the Left-Nav Categories section,
     Choose [General]

3.  In the Basic Tools detail section,
     Change "Touch Mode" from "Auto Detect" to "Never"

4.  In the Left-Nav, [Documents] section,
     Uncheck [ ] "Allow documents to hide the menu bar, toolbars and windows controls"

5.  Close Acrobat Reader, and re-open a pdf to test.


Other Recommended Acrobat Reader Options:

I recommend making these additional changes to Acrobat's default settings.

a.  In Left-Nav [Page Display],
    Set Page Layout to "Single Page". 
    Set Zoom to a default value, such as "85%" 
    (literally type the value, even if not on the pull-down selection list)

b.  In [Forms], set "Auto-Complete" to "Off". 
     This is a security measure.

c.  In [JavaScript], uncheck [ ] Enable Acrobat JavaScript.
     This is a security measure and I doubt any documents you read will be impacted.

d.  In [Search], change "Maximum Cache Size" from 100MB to 10MB,
     Then click "Purge Cache Contents". 
     The default value is obscenely large.

e.  In [Usage Information], consider turning off 'Yes, I would like to share anonymous..."


Hiding the Annoyingly Stupid Right-Pane tools bar:

For Acrobat versions 11 and older (this does not work for Reader DC)

1.  Confirm Windows Explorer (File Explorer) shows hidden and system files
     (steps not detailed here).

2.  Tunnel to C:\Program Files (x86)\Adobe\Reader 11.0\Reader\Services


3.  Delete these 2 files:
    DEXShare.spi
    DEXEchoSign.spi

     If these files are not visible, confirm Step 1.

For Acrobat Reader DC, there does not appear to be a way to hide the right navigation bar.  Perhaps it is time to consider the Foxit Reader?

Related:
Keyliner Article: Time to remove Adobe Acrobat Reader 
With all of the problems with Acrobat Reader, I made the change.