I have a word dcx with a number of non-standard words shown as spelled wrong. Suddenly, Word 2010 decided to no longer highlight any of them and an error message popped up saying that there were "too many spelling errors" to display all of them.

That's obviously nonsense, as I have 8 GB of RAM and multiple cores, with Office using only a small fraction of that. How do I fix that? Adding 1,000+ word to my custom dictionary is NOT a solution.