Please
carefully work through the following step by step.
Basics. Please state - as the forum prompted you, twice- your full Windows build number.
Then please confirm the iso file build used and base language match those of your installed O/S.
If unsure, there are tutorials to show you how to check these.
Confirm you have at leat 30Gb free on C:
Now please check your disk(s). Download and use
Hard Disk Sentinel (trial- excellent- includes SSDs) - portable version available.
Post a screenshot of the result on its GUI for each disk.
If ok, then run
chkdsk c: \scan
from an admin command prompt and advise if that passes.
Please complete specs for your PC. See My Computers under my post for comparison. There are tutorials to help you get specs and fill them in if needed.
Please state what security software is in use.
State whether you've relocated any folders to another drive or partition.
Please download a copy of
setupdiag.exe (free from MS). Run that and post the result.
https://docs.microsoft.com/en-us/win...upgrade-errors
First boot phase: Boot failures in this phase are relatively rare, and almost exclusively caused by device drivers. Disconnect all peripheral devices except for the mouse, keyboard, and display. Obtain and install updated device drivers, then retry the upgrade.
Confirm you disconnected all unnecessary peripherals.
More:
Fix: The Installation Failed in First Boot Phase Error
Thanks.