Same here while trying to install a Konica-Minolta magicolor 1650EN. That was working fine in Xenial 16.04. Then happen the switch the the GNOME in Focal 20.04 and bing ! Impossible to select any PPD file, as the GNOME settings window crash repeatidly ...
Thumbs down for Ubuntu. The system is unworkable, until someone devise a command line way to install a printer properly.
At the end I found a solution :
Click on Additional Printer Settings ... button and select your printer. in my case magicolor-1650 then right click on it and select Properties.
On the line Device URI click change
Select --> Add Network Printer
Connection should be : AppSocket/HP Jet-Direct
Host : 192.168.1.51 (compute here the IP address og the printer)
Port Number : 9100
Which is Device URL : http://192.168.1.50:9100
Don't try to install the PPD by clicking on Make and Model Change button ... It will crash everytime there ...
Go back to the choices available in the GNOME Settings for the printer magicolor-1650 clickiing on the wheeled cirecle and set the printing options like pages etc ... Then click on Printer Details and click on the Install PPD File button ... Select the PPD you have previously downloded on your system from the manufacturer website.
And that's it. T have access to defined printers on your system you have to go back to the Additional Printer Settings. From where you can priint a Test Page.
