ADL -
The "UUT" custom data type is used by the process models to share information about the UUT under test. This data type is defined in the process model sequences. This version of the type default to the version specified by the TestStand engine when we release. If you want to add things to it, you can. You will need to add your new properties to the type, up the version of that type, which will remove the "modified" flag. All of your sequences that use an instance of this type will have the new property. This includes the database logging mechanism.
The only issue that you will have to deal with is when you upgrade to a new version of TestStand, you will have to make sure that you edit the new UUT type in the new version of TestStand to match the older one so you do not loose your changes, or you can up the version of your copy above the one that the new TestStand ships with and that will replace the copy in the new version of TestStand.
You should only do this with custom data types, not NI step types or our standard data types.
Scott Richardson
https://testeract.com