A user has to complete ten steps to achieve a desired result. The ten steps can be completed in any order.
If there is a bug, the bug is dependent only on the steps that have been taken, not the order in which they were taken (i.e., the bug is path independent).
For example: If the user performs three steps in the order 10, 1, 2 and produces a bug the exact same bug will be produced if the user performs the same three steps in the order 1, 2, 10.
What is the maximum number of unique bugs this program can have?
You mean what is the number of distinct sets pickable from 10 elements? That's a powerset: 2**10.
Much later: some knowledgeable others have suggested that having no bugs should not be counted as a bug. Accordingly, I revise my count: 2**10 - 1.