This policy setting allows you to configure reparse point scanning. If you allow reparse points to be scanned there is a possible risk of recursion. However the engine supports following reparse points to a maximum depth so at worst scanning could be slowed. Reparse point scanning is disabled by default and this is the recommended state for this functionality. If you enable this setting reparse point scanning will be enabled.If you disable or do not configure this setting reparse point scanning will be disabled.
Windows Components\Windows Defender\Scan
At least Windows Server 2012 Windows 8 or Windows RT