I get around the problem by not giving important business presentations, executing long-running business management tasks, or running critical business processes on anything labeled "home edition" or otherwise labeled for non professional/business use. E.g. I buy the edition suitable for my purposes, such as Enterprise or Professional where I can control updates.
1) I use what I'm given, I'm not in purchasing.
2) The names denote featureset, to suggest you shouldn't use a home edition for "professional" presentations when it meets the required features (connects to projector, can run presentation software) is disingenuous.
Has it occurred to you that an accountant shouldn't have to use group policy? In good software the users are able to achieve their desired aim in their desired fashion, in bad software the software is always right the heretics must be burnt.
I wouldn't say this is reflective my experience in the wild world...
I'm seeing quite a lot of putting-the-cart-before-the-horse. It's fine to worry, but don't act like these major issues have already happened, or like Microsoft will not be responsible to their customers by improving testing to help ensure major breaking updates don't get out. Make a scene when it happens, not before.
The original problem I posted did happen. On Windows 8.1. Besides prevention is better than a cure.
And there is no excuse for installing an insider preview build on a production machine. None. While it is far from guaranteed, anyone who is using an insider build assumes there is some risk that their install will eventually get screwed up beyond recognition, and that the only recourse is a wipe/reinstall. "But, but..." No. No buts. Either assume the risk or get out of the program.
Did anyone in this thread claim to be running Win 10 on a production machine? Most, if not all, posters are discussing either problems with Win 8/8.1 or <I>potential</I> problems with Win 10.