Sometimes, for various reasons, the default application for certain types of files will get misconfigured. This happens often enough that users should know how to rectify the situation themselves.

We frequently see where documents of the file-type .pdf get configured to be opened by Microsoft Excel, which can't actually view or edit PDF documents.

What we need to do is change the setting back so that PDF documents are opened by Adobe Acrobat DC again:

1. Use the file manager (explorer.exe) to browse to any valid PDF document
2. Right-click the PDF file and choose