Cool that it is fixed now on Win 10 1507. Do you know what changed on / for those VMs? Or when that stopped being flaky? And can that be applied to the Win7u VMs too?
Come to think of it: there are 7 different flavours of newtb-win7u but the test is flaky only on 3 of them. That's very puzzling.
Anyway I know why we mark tests as flaky. But in this case it is a big hammer for no benefit. That area of the code needs more work, most likely a rewrite and I would hate to silence some tests and slip a regression through the CI. While Win7 is still "supported" for tests it has no priority to be added to the CI; I've watched Alexandre's gitlab roadmap presentation.
Iff those seldom win7u test failures are a problem for any CI I am willing to accept a patch that adds a:
broken(hr == DMUS_E_LOADER_BADPATH) /* Flaky on some win7 */
With broken() being superior to flaky as it applies only to Windows results and not to Linux where the test is rock solid.