How to reproduce:
(setq imaxima-latex-preamble "\\usepackage{amsmath}") in Emacs,M-x imaxima in Emacs)load("mactex-utilities")$Cause:
imaxima redefines \boxed and \operatorname.
Workaround:
use
(setq imaxima-latex-preamble "\\usepackage{amsmath}\n\\let\\boxed\\undefined\n\\let\\operatorname\\undefined")
instead, effectively undefining these commands after amsmath is loaded.
Suggested permanent fix:
in imaxima.el, \boxed and \operatorname should be defined using \renewcommand.
Fixed by commit 6dc10134 (use renewcommand as suggested). Closing this report.