Could this cause multiple identical GUIDs?

Question

As GUID generation is time-dependent, if System.Guid.NewGuid() is called multiple times at the exact same instant on different threads, could it return identical GUIDs?

Answer 1

On Windows, GUIDs (UUIDs) are created from a cryptographic random number generator with UuidCreate. They are version 4 UUIDs in terms of RFC 4122. No timestamps or ethernet cards are involved, unless you're using old school version 1 GUIDs created with UuidCreateSequential.

See also How Random is System.Guid.NewGuid()? (Take two)