I remember when I bought my iMac years ago, an HP PSC 1510 was purchased along with it and I wrestled with the config to make the two hardware pieces see each other and play nice. Since then, the hard drive crashed and now it’s the whole thing all over again.
Like most things these days, the troubleshooting began with a Google search and there was a wealth of information from others with the same problem. Turns out that HP and my iMac simply don’t play real well together.
There was lots of funky advice about unplug, power off, uninstall, reinstall, blah, blah, blah… What finally worked was to download much older drivers than the ones on the HP website and install those. Turns out that the manufacturers improvements to the drivers broke them.