Error: No PDF file was created because Adobe Acrobat encountered an unidentified error.

Unable to combine PDF files, getting an error "No pdf file was created  because Adobe Acrobat encountered an unidentified error."

Issue

When combining MS Word files to PDF using Acrobat, the following error occurs:

Environment

Windows 7 Professional x64
Adobe Acrobat

Cause

This issue occurs when Skype for Business 2016 Basic installation creates a registry key for Office 2016. Skype for Business 2016 Basic is released with some basic Office 2016 components, but it is not available with Mso.dll.

Resolution

Following are the steps to resolve the issue:

1. Ensure that MS Office and Acrobat are closed.
2. Go to Windows Registry editor.
3. Take a backup of your Registry.
4. Navigate to the registry key path: HKEY_CLASSES_ROOT\TypeLib\{2DF8D04C‐5BFA‐101B‐BDE5‐00AA0044DE52}
5. Expand the key.
   One or more subkeys are visible.
   Identify the ones that do not match the versions of Office you have installed. If all of them do match with the installed Office versions, skip the steps 6 and 7.
   • 2.3 for Office 2003.
   • 2.4 for Office 2007.
   • 2.5 for Office 2010.
   • 2.6 and 2.7 for Office 2013. (2.6 and 2.7 are acceptable for Office 2016 also, if there is a reference to Office16 under 2.7.)
   • 2.8 for Office 2016.
6.  Delete the keys that correspond to the versions of Microsoft Office that you do not have. To delete, do the following steps:
   1. Right-click 2.x key that does not belong to the office you have installed.
   2. Select Delete and confirm the deletion.
   3. Repeat the steps a and b for each 2.x key that does not belong to the office you have installed.
      
      The {2DF8D04C-5BFA-101B-BDE5-00AA0044DE52} key can occur in more places. Mostly, they all have the same subkeys, but not always, so examine each instance.
7. To access each of them, tap the F3 key. For each one, repeat steps 5 through 7.

Combine the files again.