Set Adobe Acrobat as the PDF Default in Windows 10
If you have Adobe Acrobat installed but PDF files unexpectedly open in programs other than Adobe Acrobat, set it to be your PDF file default app:
Hold the Windows logo key (just to the left of the space bar) and, while doing so, press i -- this will bring up the Windows Settings console. When this console appears, click on "Apps."
When "Apps & features" appears, click on "Default apps" at the left.
To find "Set defaults by app," pictured below, you may have to scroll down, depending on the computer's screen size.
On the "Set defaults by app" page, click on Adobe Acrobat DC, which will reveal the Manage button; click on it.
For any of the file types listed at the left that do not already have Adobe Acrobat DC listed as their default, click on whatever app is listed and choose Adobe Acrobat DC, instead. In this example, Microsoft Edge was the app associated with the .pdf file extension. Click on the app to change and then select Adobe Acrobat DC
There will likely be two listings which do not have an app associated; you can leave those alone. When finished, these file types listed at the top should look like this:
Any settings changes made on this page are automatically saved. You can close that console when finished.