Is a GUID unique 100% of the time?

Question

Is a GUID unique 100% of the time?

Will it stay unique over multiple threads?

Answer 1

GUID stands for Global Unique Identifier

In Brief: (the clue is in the name)

In Detail: GUIDs are designed to be unique; they are calculated using a random method based on the computers clock and computer itself, if you are creating many GUIDs at the same millisecond on the same machine it is possible they may match but for almost all normal operations they should be considered unique.