Microsoft released the KB5075039 update for Windows 10 to fix a Windows Recovery Environment issue that prevented users from accessing the troubleshooting tool.
The update resolves a long-standing problem that blocked system recovery efforts for affected users. The fix addresses a flaw introduced by a previous update released in October 2025.
In October 2025, Microsoft confirmed that the KB5066835 Patch Tuesday updates broke USB mouse and keyboard input in the Windows 11 Recovery Environment. The company did not disclose until February that the Windows 10 KB5068164 update also broke WinRE. “This update contains an issue that prevents the Windows Recovery Environment from starting successfully,” the February update changelog stated.
Microsoft released the KB5075039 update on March 3, 2026, to fix the WinRE issue introduced by the October 14, 2025, KB5068164 update. The changelog states, “[Windows Recovery Environment (WinRE)] Fixed: WinRE would not start after installing the October 14, 2025 update KB5068164.”
The KB5075039 update requires the WinRE partition to be at least 256MB in size. Users with smaller partitions must resize the partition and back up data beforehand.
The Windows Recovery Environment is a minimal troubleshooting environment used to repair or restore the operating system after it fails to start. It is also used to diagnose crashes or remove malware.
