heisenbug

heisenbug - n., (computing) a software defect that alters its behavior or disappears when one attempts to isolate it.


Named by analogy from the Heisenberg Uncertainty Principle, which is yet another metaphoric extension that misses the point of the original but never mind that, and as such pronounced HEYE-zen-bug. It's not as farfetched as it might seem, given that debugging tools alter the computing environment, and if the bug is caused by mis-setting the environment ...

Am unable to find when it was coined, but was in use by at least the mid 1990s.

---L.