Adobe - Set As Default PDF Viewer
This explains how to set Adobe as the default application for viewing all PDF files. Most times when another application opens PDF files it’s because of default app permissions.
Instructions
Method 1:
Right-click a PDF file name and select Properties.
Next to where it says Opens with, click on the button named Change
Select Adobe from the list of apps and then select Set default.
In the Properties windows, select OK.
Method 2:
Go to computer Settings > Apps > Default apps
In the Search apps field, search for Adobe Acrobat then click on it.
In the list of file types, search for .pdf. Click on the application that is set to open it by default.
In the new window that appears, click on Adobe Acrobat then click Set default.