Word File can not be opened, because the content causes errors. (Word 2007 and Trados 2017)

I am having a serious problem with all Word files that cannot be opened. I work with Trados Studio 2017 and when I export a translated word file I get the error: Problem with the content. File can not be opened, because the content causes errors.

Details: unknown error
Position: component:/word/document.xml, row: 2, column: 271900

I had the same problem with a word file from our translation agency. But the translator could open the file without problems. Than I asked the translator to save the file again and sent it again, after that I could open it.

Is that a setting problem with word or trados? 

We work with word 2007. And the problem occurs with files who have special template.