After certain updates you may need to change your default PDF handler. To do this, find a PDF file on your computer, right click, and hover over "Open with" then, at the bottom of the list that appears to the right, click, "Choose another app"
Next, choose your preferred PDF handler (application) by clicking it once. This will highlight your selection. Finally, click "Always" so your PDF files always open with this specific handler. If you want to open a PDF file in a different handler just this one time choose the, "Just once" option instead.
