Endless save loop in Microsoft Word
It's a Word bug. It sometimes manifests itself when working with formulas and affects versions 2007 and 2010, possibly newer ones too.
To avoid re-typing formulas or saving in compatibility mode (which converts formulas to images):
- Install a clipboard manager (Ditto Portable is a good one and you don't have to actually install it, it's a self-extracting archive).
- Switch to Word, press Ctrl+A to select everything and copy it.
- Use clipboard manager to export clipboard to a file. Clipboard should be preserved anyway, but do it just in case.
- 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.
- Open Word and paste your document. If it's not in the clipboard anymore, import it with clipboard manager first.
- Saving as docx should now work.
Answer from comments in OP:
I retyped all the formulas in a new document, and now it saves without issues.
I finally fixed this by simply following the "Open and Repair" feature in MS Office 2013 (probably in 2010 as well). Check it out - http://support.microsoft.com/kb/893672. This told me my errors (text box and a shape).
Afterwards I put my 2010/13 styles back on while in 2013, saved, and everything took. I hope this helps.