I cannot print my fm files. I have FrameMaker 2015 and Windows 10. The error message I get is "Cannot print because the selected default printer is not compatible with Frame Maker (Cannot query escape 768)"

I have exactly the same error message and have not been able to resolve it yet. Using Windows 10 and FM 2017 as part of Tech Comm suite... have always used Acrobat to print to pdf so a compatibility issue seems unlikely! No obvious change since it last worked. I think it had worked after the W10 last big update. Signed in and out of Adobe account (that has cleared a previous won't print message) and that didn't work. Full computer restart doesn't work. Acrobat is set as default printer in windows settings. Have tried checking print to CMYK checked (saw someone recommned that over RGB somewhere). I need to print a long book, not just a document. Trying to save book as pdf crashes everything.
Ah.... so save book as pdf has finally worked.... although looked as if it all crashed, left long enough (walk away, go de-stress somewhere) it recovered. But the pdf file is 5 times the size of a previous 'print to pdf' file....huge.
Any help with resolving this error and getting back to print to pdf working would be very much appreciated.......