Hi T M N Irish, sorry to hear about this problem.

If you haven't already, could you try resetting the printer's settings previously stored by Firefox. This article has the steps:

Fix printing problems in Firefox

If the problem affects a physical printer, you might test with the "Microsoft Print to PDF" printer when the print dialog comes up.

If the print dialog doesn't come up at all, Firefox may be having some difficulty communicating with Windows. I'm not sure how to track down the cause of that.

Thank you for that reply. I had already come across the article you mention and even done the prefs.js stuff, but that did not fix the prblem. Today I tried your suggestion of using Microsoft Print to PDF as the printer and ticked the box output to file, but that did not fix the problem either. I used ctrl-alt-del to open task manager. There were three firefox processes and the bottom one had not respomding against it. I have checked a few minutes ago and neither Windows 10 Pro 1909 nor Firefox 73.0.1 (64-bit) seem to want updates. I really do not thimk there is anything wrong with the printer as I have printed two documents from Thunderbird and Adobe Reader DC already today. I must admit that I was rather hoping that I would not be the only person with this problem. If I am, I have absolutely no idea what to do about it.

2020-03-08 17:00 GMT

More detail. Open Firefox, open menu, click on Print. You get a print preview of the first page of the website. My home page is just an ECOSIA search page. Click on Print... A Print dialogue box comes up with the correct printer highlighted. Click on Preferences and a XEROX Printing Preferences dialogue box comes up. This is just a test, I do not want to change anything, so I click on Cancel. The Print dialogue box is still there. I do not actually want to print, so I click on Cancel. Now I click on Close the print preview. It does not close and the top of the screen now reads "Ecosia - the search engine that plants trees - Mozilla Firefox (Not Responding)"