Problem with HP printer driver
First, apologies for earlier misrepresenting this, in a previous post, as Catalina. It's actually Mojave.
Very abruptly, my MacBook Air running macOS 10.14.6 cannot print to my HP Deskjet 6540 printer. This computer/printer combination has been working flawlessly for years -- until today (the first time in several days I've tried to print). Having just come from the HP support boards, I can tell you that this is happening to many users with a variety of Apple computers and HP printers. Reinstalling the HP driver DOES NOT help. (Said HP driver has NOT been updated recently.) I suggest that Apple seriously consider the possibility that a recent macOS update has caused this problem.
MacBook Air 13″, macOS 10.14