With the latest update of Windows 10 you might notice that the default PDF viewer is now Microsoft Edge.
To change back to Adobe Acrobat Reader, follow these instructions:
Click on the Start symbol
and type default app settings in search box and click on Default app settings under best match
Then click on Choose default apps by file type
STEP 3. Scroll down the list until you find .pdf PDF File with Microsoft Edge as the default app and click on the program name eg. Microsoft Edge.
When the Choose an app dialog box opens, click on the app you want to use (Adobe Acrobat Reader DC in this example) as the default. If no app is shown, click on Look for an app in the Store. This will open the Windows Store and you can then search by file type for a program.
You have now changed the default PDF app to Adobe Acrobat Reader DC and can now test opening a PDF file
Use this tutorial as an example and if you used a different PDF viewer previously, then select that app instead of Adobe Reader.
NOTE: Sometime the default icon for opening PDF's does not change until a restart of your computer
