This Word saving loop is a random issue that occured in AQ 57 where students were unable to save their work when they are working with fformulas and tables. This word bug does not have a fix that I can find. This issue is completley random and impossible to test without a live student not able to save their work. The following are possible solutions that could fix the issue. 

1) Save the document as a 97-2003 document to a flash drive. This has not been tested but offered as a possible solution. 

2) Copy work to a clipboard manager - 

1. Install a clipboard manager (Ditto Portable is a good one).
2. Switch to Word, press Ctrl+A to select everything and copy it.
3. Use clipboard manager to export clipboard to a file. Clipboard should be preserved anyway, but do it just in case.
4. Close all instances of Word. Copying everything to a new instance will work, but you need a full Word restart first. It may throw some errors when closing the last window, ignore them. Kill it with Task Manager if needed.
5. Open Word and paste your document. If it's not in the clipboard anymore, import it with clipboard manager first.
6. Saving as docx should now work.

http://superuser.com/questions/603393/endless-save-loop-in-microsoft-word