If a program is known to cause crashes, bugs, or otherwise conflict with Windows, Windows may remove it to keep your system stable.
You can’t necessarily just copy a program’s files to your current Windows installation, as any registry entries the program depends on may be gone. However, this trick will allow you to recover any files Windows removes. We didn’t actually run into this issue with the November update ourselves, but we’ve seen many reports of it and know people who have.
Unless Microsoft changes its mind, Windows 10’s big updates will continue to automatically uninstall various programs without any notice in the future.
In some cases, people even reported that it removed PDF viewers and antivirus programs (perhaps outdated ones). In fact, Microsoft specifically declined to comment when asked about this by Venture Beat.
Confusingly, it seems like the Windows update removed these programs from some computers but not others. We also haven’t seen them issue a statement to any other media outlet or a blog post on the subject.
It will only remove programs when updating to a new major version, or “build,” of Windows 10.
That’s because these major versions, or “builds,” are treated differently from normal Windows updates.
As part of the upgrade process, Windows leaves your old Windows installation–or old Windows build–files in the “Windows.old” directory on your system drive. This is also displayed as “Previous Windows installation(s)” in the Disk Cleanup application.
Windows may remove programs during an update for compatibility reasons.
Here’s what’s going on, and what you can do about it.
To start: Windows won’t just remove programs at random times.
This allows you to roll back to the previous build of Windows 10 if you have a problem.