Self-disconnecting printer
Q Printing to my Epson DX7400 printer works normally, but its Dock icon and pop-up windows warn that it isn’t connected. This started after updating to 10.12.5, with the printer connected to my Mac mini and shared from there. Is this a network problem? by D av i d Wa r d A Before worrying about whether there is a network problem, first check the version of the printer driver you’re using. If you have Epson’s own software, note that it hasn’t been updated since November 2016, and will probably be version 2.22. If you have the driver provided by macOS Sierra, it should be version 9.0, and updated via the App Store.
Uninstall any older driver and other Epson software first. Next, in the Sharing pane on your Mac mini, turn Printer Sharing off. Then in the Printers & Scanners pane on both Macs, select the Epson in the left side and click on the ‘–’ tool below to remove the printer. Close that pane and open it again, and add the printer back using the ‘+’ button. That may trigger a software update in the App Store app, to fetch and install its current driver.
Once you’ve turned Printer Sharing back on, install the printer again on your other Mac, and you should find it remains properly connected. If not, check that your network is all in good order, with all network cables securely inserted and safely routed.