Protected Mode - Windows 8.1 - IE in browser PDFs

Windows 8.1 Enterprise x64bit

Latest Windows updates as of 8/12/2017

Adobe Reader DC 2018.009.20050

IE: 11.0.9600.18838 (with Adobe Add-on enabled)

With protected mode turned on, issue when opening PDFs from IE when add-on is enabled. Error: "There is a problem with Adobe Acrobat/Reader. If it is running please exit and try again. (0:104)."

How to replicate:

Go to Google.com on IE

Search: PDF test file

Click the first in the list. e.g. https://graduateland.com/api/v2/users/jesper/cv

"There is a problem with Adobe Acrobat/Reader. If it is running please exit and try again. (0:104)."

Reading and testing I made a custom protectedmode config file to try exclude everything and work my way back to fix however that also errors, you can see those custom exlusions below. ProtectedMode Log file below.

[12:08/13:21:35] Adobe Reader Protected Mode Logging Initiated

[12:08/13:21:35] Found custom policy file: C:\Program Files (x86)\Adobe\Acrobat Reader DC\Reader\ProtectedModeWhitelistConfig.txt

[12:08/13:21:35] Adding custom policy: FILES_ALLOW_ANY = *

[12:08/13:21:35] Adding custom policy: PROCESS_ALL_EXEC = *

[12:08/13:21:35] Adding custom policy: REG_ALLOW_ANY = *

[12:08/13:21:35] Adding custom policy: MUTANT_ALLOW_ANY = \Sessions\1\BaseNamedObjects\*

[12:08/13:21:35] Adding custom policy: SECTION_ALLOW_ANY = \Sessions\1\BaseNamedObjects\*

[12:08/13:21:36] NtCreateKey: STATUS_ACCESS_DENIED

[12:08/13:21:36] real path: \REGISTRY\MACHINE\Software\Adobe

[12:08/13:21:36] Consider modifying policy using this policy rule: REG_ALLOW_ANY

[12:08/13:21:36] NtCreateKey: STATUS_ACCESS_DENIED

[12:08/13:21:36] real path: \REGISTRY\MACHINE\SOFTWARE\Wow6432Node\Adobe

[12:08/13:21:36] Consider modifying policy using this policy rule: REG_ALLOW_ANY

[12:08/13:21:42] Invalid path: \Device\HarddiskVolume2\Users\MYUSERNAME\AppData\Local\Adobe\Acrobat\DC\

[12:08/13:21:42] Invalid path: \Device\HarddiskVolume2\Users\MYUSERNAME\AppData\Local\Adobe\Acrobat\DC\

[12:08/13:21:42] Invalid path: \Device\HarddiskVolume2\Users\MYUSERNAME\AppData\Local\Adobe\Acrobat\DC\

[12:08/13:24:22] Exit Code:1

As you can see looks like its still having issues reading. \REGISTRY\MACHINE\Software\Adobe

I've uninstalled/re-installed manually and still having the same issue. Any suggestions?

I would really like "Protected Mode" to be left on by default with the IE add-on.

Same version works fine on Windows 10 x64bit.