Cross-references corrupt on saving a masterdocument

[SimonGroom]

I'm in the final stages before printing of my graduate thesis, so I'm dealing with a 7 sub-document master document of 60 000 words and 50-odd figures... And a glitch just turned up in word.

I built this as a master document, and largely edit each sub-document separately. But i've been getting glitches where I cross-reference to figures, with the figure itself turning up in the cross-reference field, or just a blank line added. I've seen this discussed here in terms of "hidden bookmarking", and it seems to be a well-observed glitch. I've tried deleting the fields, and initially it looks ok.

However, when I re-open the master document, and save it again, the glitches re-appear. Historically there is some bad feeling towards corruption of master documents, so I'm worried about the whole 60k document... Can master-doc problems link into cross-referencing problems?

Thanks for your help.