Lightroom 6 Print Module will not print- is this a bug?

[kerredding]

I am using a Macbook Pro, running Mac OSX Sierra (10.12.1), Lightroom 6 (6.1) and an Epson 3880 Printer. This set up has worked beautifully for three years.  Now this has stopped working. I can print to the printer from other applications (Export image-->Open in Preview--->print-->success) but not from Lightroom.

When I go to print I follow this workflow:

1. Check the page setup to select my printer and paper size here:
2. Next I choose either PRINT or PRINTER from the bottom right of the screen. Usually I click PRINT and it works. Now I click PRINT and it appears as though a print job is being prepared but then nothing happens. The job never even appears in the print queue.
3. When I choose PRINTER usually I can select PRINT from this dialogue box but instead I only see the SAVE option- not a PRINT option as seen here:

I have uninstalled and reinstalled the printer software several times, no success.

I have uninstalled the software, restarted the computer, reinstalled the software several times, no success.

Additional information- when I choose PRINT SETTINGS, make the adjustments and click SAVE a dialog box opens asking me where I want to save- this has never happened before. (I thought when I saved the print settings it was saving information about my specific print job to a setting file-?) If I choose SAVE then Lightroom saves the current image I am working on as a PDF file. (WHY?!?!)

Any and all help is appreciated. I teach Photography in a high school and all the students are also using Lightroom about to move into a unit where they are printing their own images. I am hoping this is not a bug and simply...well, something I can fix, quickly.

The students are using various iMac models all with Lightroom 6.1 and Mac OSX El Captain (10.11.6). When I load my LR catalog on a student machine to print I do not have any errors. Same workflow as above EXCEPT when I choose PRINT SETTINGS on the student machines and click save there is no dialog box asking me where to save a file. I click PRINT and it prints as expected.

Can you help? Thank you- Kerri