Zebra 105sl printer shows Error Code: ribbon out Printer Idle: 60-16-3z after we moved it from a different location. However, we've been printing fine w/o ribbon for many years.

So u used the direct thermal label that doesn't need a ribbon ? check the driver at Printer & Faxes on the PC, change the print method on the printing preference from thermal transfer to direct thermal

The default setting is thermal transfer for this printer. You can change the setting on the printer so it doesn't show you the error any more by doing the following:
Press SETUP/EXIT Press Plus (+) to scroll through the different parameters About the 6th parameter is "PRINT METHOD" Press "SELECT" to select the parameter Press Plus (+) or Minus (-) to change to Direct Thermal (no ribbon) Press "NEXT/SAVE" to save your changes