File validation in Word must be enabled.
This policy setting allows the file validation feature to be turned off.
If this policy setting is enabled, file validation will be turned off.
If this policy setting is disabled or not configured, file validation will be turned on. Office Binary Documents (97-2003) are checked to see if they conform to the file format schema before they are opened.
How this relates to the STIG checklist: STIG vs SCAP benchmark.