I think the issue for me is their overwhelming lack of respect for their users during the Windows 10 "free upgrade" push. The heavy-handed GWX nagware push, the use of dark patterns like switching 'Install' and 'Cancel' buttons, repeated re-issues of the update which installs GWX. Then there was the telemetry built into Windows 10, which "could be turned off" but mysteriously kept re-enabling itself. Then pushing that telemetry into earlier versions of Windows via updates. Now rolling updates into monthly undocumented blobs.

To regain any kind of trust from me, they'd need to begin with a public apology for their approach, and a commitment to a far more open, accountable, and respectful approach in future towards their users' privacy and autonomy over their own systems.