DTOO119 - Configuration for file validation must be enforced.
This policy setting allows you to turn off the file validation feature. If you enable this policy setting, file validation will be turned off. If you disable or do not configure this policy setting, file validation will be turned on. Office Binary Documents (97-2003) are checked to see if they conform against the file format schema before they are opened.
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Word 2016 -> Word Options -> Security 'Turn off file validation' to 'Disabled'.