Windows Media Player just produced a wonderfully cryptic and nerdy error message:

operation attempted in an invalid graph state

For on thing, this is not the sort of error message you want to expose to an end-user — it’s the sort of debugging message that could only make sense to someone dealing with the program’s source code. I can make an educated guess about what it might be referring to, in general—something to do with a state machine and/or dynamic playlist management, perhaps— but for one thing I’ve got a degree, for quite another even that doesn’t help me use the program in any way.

It’s a non-fatal error; in fact, I wouldn’t know it existed if Media Player hadn’t highlighted in orange the track apparently affected by the error, prompting me to mouse over the track to see what, exactly, that was all about. (I say “apparently” because the track played just fine, in fact. So much the better: a cryptic, not-for-users debugging message that reports an unobserved problem.)

In Microsoft’s defense, there are worse problems a program could have than tossing out the occasional baffling-but-unobtrusive developer message. (As counterpoint, of course, those worse problems have themselves been evidenced on more than one occasion by Microsoft’s software.) Further, I expect I produced this odd error by essentially grinding my machine to a halt doing a work-related search. So it feels like an edgecase — it may be that no one at Microsoft has ever seen this thing in the wild.