This is an old thread, but if anyone else comes across this:
If using LabVIEW 2020 or later, the best way to generate a GUID is to use the native Create NI GUID.vi which is found in the String >> Additional String Functions palette.
If using LabVIEW 8.0 to LabVIEW 2019, the best way is to download the Create NI GUID.vi that is found at: GUID Generation for LabVIEW Versions Older than 2020 . This is the same VI as the one that exists natively since LabVIEW 2020, but "Saved for previous..." to LabVIEW 8.0.
If using a LabVIEW version older than 8.0 on Windows, it's probably best to use the .NET Framework System.Guid object, as document in the following article: How to Generate a MessageID/GUID/UUID With LabVIEW? and as seen in the screenshot below.
This comment was cross-posted at: https://forums.ni.com/t5/LabVIEW/Any-GUID-generating-VI-available/m-p/1246596