Beginning in early October (2019) we started getting reports of instability in ACP Expert and other software. These reports coincided with the installation of Windows 10 Update(s), most notably the Windows 10 "Fall Feature Update" 1909.

Until we learn more, we are recommending that you

  • Stop Windows 10 Updates immediately. You can stop them for 30 days (see below). Then set a calendar alarm to "refresh" the stop in three weeks. Keep them stopped until we learn enough to tell you more.
  • Immediately uninstall Windows 10 Feature Update 1909 if it got installed. You only have a few days to do it. This article contains some good info, particularly if you want to bravely remove it beyond the 10 day limit normally provided. It's likely that Microsoft will issue revisions in the future, and you'll be able to get back in the flow of updates. Even if you think everything is OK, uninstall it. We don't know what may be lurking there, and you don't need those "cool new features" for astronomy anyway.

If you still have problems, look for other recent Windows 10 updates that might coincide with the beginning of your problems, and remove them. You don't need to worry about Definition Updates, or updates for .NET or Flash Player., just the ones for Windows 10 itself. Here's a screen shot from a system that has not received 1909, and it shows just two updates for 1903 that you could remove if yuou suspect them of causing problems. Don't do this, though, unless you have problems that "just started happening" and you can see a recent Windows 10 update about that same time!