HP makes incredibly good printers and incredibly bad printer software, so it’ll come to no one’s surprise that when trying to install your HP LaserJet 400 401n printer, you’ll be met with an “An install operation took too long to execute” error after waiting around 20 minutes for it to finish installation at 99%.
The solution is to turn off Smart Install on the printer by entering the Service menu on the printer itself, then turn off Smart Install. Now, disconnect the printer from your computer. Next, install the printer’s basic drivers into Printer Management, then plug the printer back into your PC by USB!