0xC1900101 is an upgrade result often associated with a driver-related rollback. The extended code and setup phase are needed to identify where the upgrade stopped.
Protect your files first
Back up important files when possible. If the drive is encrypted, locate the BitLocker recovery key before recovery changes. Stop if storage appears to be failing or this is a work or school managed PC.
What the code means
0xC1900101 is an upgrade result often associated with a driver-related rollback. The extended code and setup phase are needed to identify where the upgrade stopped.
Evidence that helps
Record the full pair, such as the primary code plus an extended phase code, the current Windows build, and connected devices. Use Microsoft’s upgrade resolution guidance and the PC maker’s driver support for the exact model.
Avoid a false diagnosis
Do not treat every 0xC1900101 as the same driver or apply a generic firmware change.
Check the exact Windows build and the screen where the error appeared before applying a repair.
Keep track of your checks
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