PDF Not Working

On my 8.1 laptop the PDF reader is not working for the past several weeks, it worked fine before. All I get after the download is a black screen.
Any idea what is causing this?
Thank you for your responses.

What is your pdf reader app? you might try uninstalling/reinstalling the app or make Chrome the default app for .pdf (if it isn't already)

It might be worth trying a full disk clean (including system files option if a quick clean-up doesn't do the job) and also a browser clean-up. I use the inbuilt pdf reader pretty heavily and on occasions get odd behaviour. Typical things include trying to open an on line file and only seeing the last pdf I viewed as being displayed, or a message saying the file I want to view is of the incorrect format, or... it thinks about opening it and hangs and then reverts to a kind of library view of pdf's saved locally. A clean up always restores normal operation.

I right clicked on the blank screen and it is working again. Why? I don't have the faintest idea..
Thanks for your responses.