Summary: Do not upgrade your W7 or W8 observatory computer to Windows 10 for at least a year or two. If you have already done it, then you'll have to change your Windows settings to prevent late night reboots and automatic updates in order to have a stable observatory system. What's going to happen to your wonderful observing run when Windows decides to reboot at 0230? You also may need to re-run your ACP and/or Scheduler installers to repair damage caused by a particular Windows 10 update. Not always. But do not uninstall!

I need to start by saying that our software is compatible with Windows 10. However, some of the many Windows 10 updates that are usually applied without people even knowing (early AM auto-reboots, etc) have been wreaking havoc on peoples' systems, not just with ACP but with many other software packages that formerly ran fine. Back in January we got a note from ACP user Manning Butterworth after the Windows 1511 update came out:

Quote Originally Posted by Manning Butterworth
I'll be happy to share my experience. In my case, the Windows 10 upgrade to 1511 meant the mail system no longer worked, the financial software no longer worked, the document management software no longer worked, the directly connected printer no longer worked, the directly connected scanner no longer worked. This pretty much qualified as an unusable system in my opinion. By "no longer worked" I mean either the application or device would no longer execute at all or an attempt would generate an error message about missing DLLs which were not missing. After spending an entire very long day trying futilely to correct these problems, I decided it was much better to cut my losses and roll back to the original Windows 10 release. Thereupon everything worked as it had done, and I could get on with life.

A quick search revealed that there are hundreds of problems with Windows 10 build 1511. As I said in my original post, the affected system was fortunately not the one I use for astronomy. Had it been, I might have mistakenly thought the problems were hardware related.

From what I have read and from what I experienced, Windows 10 1511 is very far from being ready for prime time. I am happy for those that have upgraded without problems. But, I will not voluntarily upgrade any more systems to 1511.
Manning B
This was just the beginning. Here's a link to the Windows 10 Update History through the end of last month (Sep 2016). Some of these updates have locked the registry area where ACP saves its settings. Others have unregistered ACP's Windows Object libraries (AcquireSupport and the Plan Compiler). We just had a report of Cortana saying PinPoint has been removed, yet it is still there and seems to work fine. We're still looking into this one. This sort of thing is happening to other Windows software as well, solid software that relies on some part of windows that Microsoft decides needs "cleaning up" in an incompatible way. It might be interesting to read through the Windows 10 Feature Roadmap to see where it's going.

The good news is that I expect them to resolve these issues in the long term. We are not alone. And at Microsoft, it's basically the new guard replacing the senior engineers who were truly focused on maintaining a stable application execution environment.