Hello, the_lil. I don't work in 64-bit Office, but I'm guessing that this possibly could be causing the disconnect, if the document was created in 32, or if a compatibility issue from a much earlier version of Word could be interfering. You don't mention in which version the document was created.

Otherwise, sometimes a single element in a long document hangs up a process; but without the document, guessing is pointless. Depending on what is in your document (graphics, tables, etc.) and how much formatting would have to be redone, you could consider copying the contents into a plain text file (which will not accept table formatting or graphics), then copy this into a newly created .docx and reformat as needed. Then copy tables and graphics into a separate new .docx and see if it will save. If yes, copy them into the new .docx with the text where they should go. If it won't save, you may have to try one by one to see where the problem lies.

This may seem laborious -- well, it is laborious -- but sometimes a half hour, or a few hours, spent on such methods saves hours of frustration adn is the best investement.

I'd be interested to know how this works out for you.

Best,
Ulo