In followup to earlier post. here is what I tried:
1\ uninstall, complete reinstall of MikTeX (takes only 5-6 minutes with
my network)
2\ try compiling the following MWE
\documentclass[11pt,letterpaper]{article}
\usepackage{fontspec}
\setromanfont[Ligatures=TeX]{XITS}
\usepackage{unicode-math}
\setmathfont[math-style=ISO,bold-style=ISO,vargreek-shape=TeX]{XITS Math}
\begin{document}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent in
tincidunt nulla. Donec quis laoreet est. Aenean vitae est felis, a
venenatis magna. Mauris semper bibendum vulputate. Etiam bibendum quam
ut erat rutrum consequat.
\begin{equation}
\frac{dN}{dt}=rn\left(1-\frac{N}{K}\right)
\end{equation}
\end{document}
Compiles perfectly.
3\ fire up MkTeX updates -- update everything (lua* an everythng else).
What the heck. ;-)
4\ MWE no longer compiles. Complaints about format. Try using MikTeX's
format updating utility - doesn't work. Try from command line
initexmf --dump=lualatex
Now I generate a new .fmt file (so, the gui-based format update utility
doesn't sem to work, but doing it from the command line did)
5\ try another compile of the MWE -- still fails, but with a more
telling error messaGE:
luaotfload | db: Font names database not found, generating a new one.
Then it fails -- unexpected condition.
If I comment out
%\usepackage{fontspec}
%\setromanfont[Ligatures=TeX]{XITS}
%\usepackage{unicode-math}
%\setmathfont[math-style=ISO,bold-style=ISO,vargreek-shape=TeX]{XITS Math}
in the MWE, compiles fine. So, the problem is with fontspec (or things
related to it).
If I have a chance tomorrow, I might do another complete re-install, and
update only fontspec to see if it is the problem...
