▲ 2 r/WindowsHelp
The installation failed in the Safe_OS phase with an error during boot operation.
Upgrading Windows Server 2019 → Windows Server 2025 is consistently failing during setup rollback with:
0xC1900101 – 0x20017
“The installation failed in the SAFE_OS phase with an error during BOOT operation”
The upgrade starts normally, copies files, reboots, then fails during the SAFE_OS / BOOT phase and rolls back to Server 2019.
u/AmmadIrshad — 6 days ago