An update on my continuing problems creating custom profiles using the z9+ and MacOS:
After reading some of Mark Lindquist's postings elsewhere in the printing forum I am now realizing that the incompatibility is probably between the HP Designjet Print Utility and the MacOS rather that between the printer's firmware and the MacOS. So I will try to download an older version of the print utility that Mark is offering to us on the forum and see if that solves the problem.
Furthermore, I have now been in communication with the Designjet High Value Team engineers in Ottawa, Canada for over a year regarding this issue. The latest engineer assigned to me has been extremely helpful and even went to the trouble of bringing a z9+ printer and mac computer into his personal workspace to attempt to duplicate my problem. He confirmed that, at least Mac 10.14.2 and the z9+ would not produce custom profiles and that he received the same error message that I continually get.
His last communication with me last week indicated that HP software engineers were currently in contact with Apple engineers in a attempt to resolve this problem.
That said, I am still extremely happy with the prints I am making using existing Hahnemuhle profiles.
Ken Susman
Mendocino, CA