Policy
Do not automatically merge server and local document
This policy setting determines if changes made to a server document should be automatically merged with the locally-cached copy of the document on the next save. This policy pertains to the co-authoring experience in Word. If you enable this policy setting, then changes made to a server document will not be automatically merged with the locally-cached copy of the document on the next save. If you disable or do not configure this policy setting, then changes made to a server document will be automatically merged with the locally-cached copy of the document on the next save.
b636971233f0 L_DoNotAutomaticallyMergeServerAndLocalDocument Registry
Copy registry mappings
HKCU\software\policies\microsoft\office\16.0\word\coauthoring\disableautomerge (enabled) = 1
HKCU\software\policies\microsoft\office\16.0\word\coauthoring\disableautomerge (disabled) = 0Policy notes
This policy setting determines if changes made to a server document should be automatically merged with the locally-cached copy of the document on the next save. This policy pertains to the co-authoring experience in Word. If you enable this policy setting, then changes made to a server document will not be automatically merged with the locally-cached copy of the document on the next save. If you disable or do not configure this policy setting, then changes made to a server document will be automatically merged with the locally-cached copy of the document on the next save.