I HAVE AN OKI MC860 MFP. WHEN I CLICK PRINT TO PRINT A LIBRE WRITER DOCUMENT THE PRINT DIALOGUE BOX HAS LIBRE OFFICE AT THE TOP. IN THIS PRINT BOX THERE IS NO DUPLEX PRINTING OPTION. I CANNOT DO TWO SIDED PRINTING IN THE NEWEST VERSION OFF LIBRE OFFICE. HAS ANYONE HAD A PROBLEM LIKE THIS?
Please try printing via printing dialog File > Print.... In the printing dialog go to tab Options and enable Use only paper size from printer preferences. Then go back to tab General select the printer in the list and click on Properties.... That opens the printers own setting dialog. There should be a setting to turn on double-sided printing (and setting the paper size), set it and close the dialog. Now you are on the General tab again. Print.
That is a long way, but should work in all cases.
If that does not work, you should export the document to .pdf and use the Acrobat Reader to print the document. It has a checkbox in the dialog for double-sided printing and a button to enter the printers own setting dialog as well. If printing via Acrobat Reader does not work too, then there is a deeper problem with your printer.
Please try selecting PostScript (Level from driver) in the Properties → Device tab of your printer. The default value is “Automatic: PDF”, which can cause problems with several printers.
I was able to confirm this workd because I couldn’t duplex print on my HD OfficeJet 8600 from LibreOffice, but all other programs worked fined. Changing to PostScript solved the problem.
I was having the same problem with my HP OfficeJet 8600 and your suggestion worked. Thank you!