"Export PDF" tool in Adobe Acrobat Pro 2020 app has stopped working
The Export PDF tool in my Adobe Acrobat Pro 2020 app has stopped working. The Export PDF shortcut in the right panel no longer works, nor does selecting the Export PDF tool under the Tools tab. Fortunately, I can work around this problem by going File > Export To > [choose type of file format]. But I'd rather be able to use the Export PDF shortcut tool, which has worked flawlessly until now.
Now, when I click the Export PDF tool, I still get the page saying "Export your PDF to any format," along with the export choices. Then I choose the type of file I want to export to, and I click the blue Export button. However, the only thing that now appears is a blank white box with a blue title bar that says "Save As." There are no fields into which I can enter the name of the file or its location.
Short of uninstalling and reinstalling Adobe Acrobat Pro 2020, does anyone know how I could restore my Export PDF tool's functionality? I see that I can remove the tool by going View > Tools > Export PDF > Remove Shortcut. I didn't try that, because I don't know how I'd re-install the shortcut.
Acrobat's Help menu says I'm running 2020 Release (Classic) Version 2020.005.30636. My OS is the current update of Windows 10 Pro.
Many thanks to the Community, in advance.

