This wasn’t a problem for the first 15 months of Windows 10, but over the last week, you can add it to this OS’s forgetfulness.
Basically, Windows 10 thinks Microsoft Edge is the default PDF opener—when since the beginning I’ve had that set to Adobe Acrobat. This bug only began surfacing last week.
No matter what I do, Windows will forget it by the time I restart the computer.
I can go into the Control Panel, then Default Programs, and associate a file type with Adobe Acrobat. That doesn’t work: even if the name changes to Adobe Acrobat in this list, Edge will still open it.
I can go to a PDF file, right-click and select ‘Open with’, then ask Windows to open PDFs using Adobe Acrobat from now on—that only works for one session.
When Acrobat detects it is not the default program, and I ask it to become that, it will give me this error (as it has done every day for the last week and a bit):
The above are the three normal ways other pages have advised on ensuring Acrobat becomes the default PDF program. None work.
Additionally, my PDF thumbnails are disappearing in favour of the Edge icon, which is useless to me.
I hope someone out there has a proper solution.