Fix Windows 11 Update Install error 0x80070bc9
Go to the BIOS settings and check if TPM 2.0 is disabled. If it is disabled, enable it and try again.Update the BIOS
Step 1) Run Update Troubleshooter
Step 2) Restart Windows Update & Background intelligent transfer service
Step 3) Use Windows 11 Installation Assistant https://www.microsoft.com/en-us/software-download/windows11
Step 4) Use Microsoft Update Catalog https://www.catalog.update.microsoft.com/Home.aspx
Step 5) Reset Windows Update Components
SC config trustedinstaller start=auto
net stop bits
net stop wuauserv
net stop msiserver
net stop cryptsvc
net stop appidsvc
Ren %Systemroot%\SoftwareDistribution SoftwareDistribution.old
Ren %Systemroot%\System32\catroot2 catroot2.old
regsvr32.exe /s atl.dll
regsvr32.exe /s urlmon.dll
regsvr32.exe /s mshtml.dll
netsh winsock reset
netsh winsock reset proxy
rundll32.exe pnpclean.dll,RunDLL_PnpClean /DRIVERS /MAXCLEAN
dism /Online /Cleanup-image /ScanHealth
dism /Online /Cleanup-image /CheckHealth
dism /Online /Cleanup-image /RestoreHealth
dism /Online /Cleanup-image /StartComponentCleanup
Sfc /ScanNow
net start bits
net start wuauserv
net start msiserver
net start cryptsvc
net start appidsvc