Will editing a Word file from a mounted Truecrypt volume leave any trace behind on the host computer?

As you can see here the proper answer is "sometimes" but given you count on your document being private you shouldn't assume the behavior of Word is safe.

If you really want to protect your encrypted documents you must use the full disk encryption because there are too many case where your OS/apps will cache data on disk (swap, temp files, filename in the registry as recent documents, hibernation...).

This is a very old thread, but I thought I'd throw in my two cents-- two cents based on direct experimentation.

Word as an application (only one of of many) can and might leave traces of edited documents that you work from a truecrypt or Veracrypt volume. After working on a Word document for many weeks directly from a secure file container in Veracrypt, I used a tool called "Recuva" to scan for deleted files on my C: drive and scanned for text strings that I knew were unique to the document I'd been working on.

Recuva found a file fragment in 'poor' condition which had been 'overwritten' by a log file in Windows/System -- the exact name and details not important.

I did a file recovery and inspected the contents. It was full of fragments of other files, but within the restored file contained large fragments of the document I'd been working on.

Now, there are many possible reasons for this. The important thing is to the best of my knowledge, I'd never moved the file off the encrypted volume, I'd never saved it locally. My best guess is it was an autorecover which was deleted from the C: drive after a successful save and close. But the exact reasons aren't as important as the mere fact that working on documents of any type from a mounted truecrypt/veracrypt volume may leave traces of themselves through whatever mechanism the particular software uses to cache, save copies or recover themselves outside of the mounted volume. As the poster above said, your BEST bet is total disk encryption.