LibreWriter (5.1.6. and 5.2.3) does not print to a file, if the system has no printer.
(Talking of Win 10 / LibO 5.x where applicable.)
Printing a document to a file means to process it for a printer, but not to send the resulting stream to the printer immediately and instead to save it to an intermediary file. (As far as I know the system’s standard printer will be used.) Therefore a printer (printer driver) must be installed. In fact you can install any printer not physically present using an arbitrary name and an arbitrary accessible printer driver to it. Even the portname may be a fake. (There also are drivers for virtual printers no hardware exists at all. You may create pdf files this way e.g.)
A file to which you printed using a not connected printer can later be printed by sending it to a printer understanding the code from a command prompt or using a script e.g. To get this work you need to choose an appropriate driver with respect to the final target when installing your not connected printer. There is no printimg to files that every printer would understand.
Have you tried File → Print → Options and then choose Print to file?
Thanks all, i understood, now working.