another good reason not to upgrade. When I buy a new computer, it will be Win10 because that will be all that is on offer.

Merely upgrading to avoid any loopholes in security that might no longer be updated is a security gamble. And this kind of annoyance is just a little cluette.

It may not be caused by Micro$oft's diligence in testing their OS, per se, it may be the the unknown and unknowable mix of your installed s/w that is far too complex & unique for them to have seen before.

Having said that I have seen an update in Office that prevented all macros from working and it was many days after they still hadn't posted a solution that the techie world knew how to. And the solution was to delete a file! And Excel would re-constitute the contents if it was not there, then everything was honky dory, except for an annoying nag screen that says Activex doesn't work, yet does. I live with that.

Let us know what solved the problemo. I usually use the three finger salute (Cntrl Alt Del) or run Taskmgr from the start screen - in Win 7 though. Very handy when using a (notso) HotSpot.