Yes I'm positive there is no \x in the switch, and there are definitely no hard returns in my heading.

Perhaps it's a Mac thing...

Or maybe a fault in your Office installation. Try checking with another Mac user.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]

I've actually just tried updating the table of contents for this same file, on a PC in an older version of Word, and had the same problem.

I might try saving back to .doc (rather than .docx) to see if this makes a difference.