The error is caused by malformed XML tags in the document's XML code; it has nothing to do with macros. Since only one user is affected, you might try repairing that user's Office installation (via Windows Control Panel > Programs > Programs & Features > Microsoft Office (version) > Change > Repair).
Word MVP Doug Robbins has repaired numerous such documents. See, for example:
https://answers.microsoft.com/en-us/...d-fef1aba81664