This topic is a genuine puzzle and my thoughts are that the method of transmitting the file is causing the problem. It appears that the file is being corrupted by some third party application because this is the kind of thing you might see if you saved the docx file as a pdf and then converted it back to docx. Is it possible that the file is being opened in some other software like Libre Office?

Is the file being emailed to your daughter? If so, what email packages are you both using? Does it make a difference if you load the docx file on to a usb stick and put the file on your daughter's machine via sneakernet.

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Andrew Lockton
Chrysalis Design, Melbourne Australia