There are many different ways to unintentionally turn off DM and break the link between a document and the «eaDocXDocument» element in the repository:

1. Saving the document under a different name
2. Moving the element to another package
3. Loading a profile into a DM document
4. Copying a document to another repository
5. ???

Once the link is broken, the only way to re-establish DM & preserve document and version history involves creating a new «eaDocXDocument» element and do a lot of copying, pasting, and re-linking.
It would be really nice to have a tools option which allows you to re-link a Word document to an existing «eaDocXDocument» element, and turn the DM feature back on.