Frustrated on failed upgrades from Windows 7 to Windows 10 on Thinkpad X200. Getting “We couldn’t install Windows 10” message, “0xC1900101 – 0x20017 The installation failed in the SAFE_OS phase with an error during BOOT operation” five times over 24 hours. Looked up experiences reported on web, BIOS up to date, antivirus removed, installed with Media Creation Tool on USB and on online download, with and without updates. Dual boot laptop with upgraded RAM and disk in 2012, normally using Ubuntu Linux with Windows as rare fallback every few months. Will stay with Windows 7 fallback, enjoy higher productivity with Ubuntu Linux.