A free tool to convert between all GUID formats needed in Office 365 Identity scenarios (Azure AD Connect, MIM, ms-ds-ConsistencyGuid...)
base64/immutableID objectGuid hex/ms-ds-consistencyGuid
Sample GUID: mPTWH3UsZ0eHLaNfh9su+Q==
hex/ms-ds-consistencyGuid objectGuid base64/immutableID