Help: Acrobat Reader DC program opens randomly with tiny empty white window without me opening it.

On my computer (Windows 10), I have a problem where the Acrobat Reader DC program opens randomly without me opening it or clicking on it. The window that opens is a small, 3-inch square white window containing only an X in the top corner (to close the window). The window doesn't say Acrobat Reader across the top, but closing Acrobat Reader from the Windows 10 taskbar closes the window. I'm sick of it popping up; it happens about 5 times per day, even when Acrobat reader is completely closed. Is there any way to troubleshoot this? Thanks to anyone who can help. I have attached a screehshot.