PC won't boot after lastest Windows 10 update

Try Booting with Supergrub  the link is below with all the instructions

https://www.supergrubdisk.org/super-grub2-disk/

I know you were concerned about losing your files, they aren't gone, just unavailable,  that is if you didn't format the hard drive.  Unfortunately with some of the reboot methods don't format but do eliminate.  If you throw in the towel, take your pc to a reputable tech and see if they can recover them to a flash drive.  Good luck.

Hi Yash,

not sure what you tried.

Tried some extra hw battle step.

with the lenovo of my brother always stuck inthe Lenovo screen without the chance to boot from a recovery usb stick or even cdrom with linux. So it must be something on the boot disk which shows this error after each win10 upgradee >1909.

Unmounted the harddisk and connected via usb ext drive casing. Booted with the usb recovery disk without the external windows boot drive and reconneted it after the boot. now from usb revovery drive i can access the boot drive and manged to rollback the win1o upgrade via the recovery options. 

Remounted the drive to the case and boots like a crazy. Blocked the windows update for the next month and hope i find out the real reason for the lockup after the an win10 upgrade on the Lenovo.

Hope this helps.

Ciao, Bernd

Hi Bernd.

Thanks for the feedback. Couple of updates below and further guidance needed, if anyone you can help. Apologies for the long message!

Retrieving My Files

Just over a week ago, I took out the hard disk from the PC. As it's a SATA HDD, I was unable to install it in an older PC as it did not have a SATA connection. So, I had to purchase a SATA to USB cable with a power adapter. For anyone reading this, if your HDD is a 3.5" HDD, you must ensure you get the cable with a power adapter, otherwise the HDD wont power up. I've heard you don't need the power adapter for 2.5" HDDs, but I cannot confirm that. 

Anyway, so I was able to connect the hard disk to a laptop as an external drive, and boom! ... I was able to access my files! That was the main problem solved, being able to access my files. 

Restoring the HDD / Lenovo PC

What I would like to do now is get the PC working again. Not sure if I mentioned it previously, but the Lenovo PC came with Windows 8.1 installed. When Windows 10 was released, there was a free upgrade for those on Windows 8.1, and so I upgraded to Windows 10. Not sure if this has anything to do with failing boot from the flash drive with the Windows 10 installation media that I tried previously. 

Anyway, to pick up on what you suggested Bernd:

Booted with the usb recovery disk without the external windows boot drive and reconneted it after the boot. now from usb revovery drive i can access the boot drive and manged to rollback the win1o upgrade via the recovery options. 

I have managed to boot from the USB flash drive, and it displays a Windows Setup window, as per the following image:

But I am a little confused as to what to do next. What should I do / select from this window? Or should I just turn off the PC, reconnect the HDD, change the boot sequence to boot from the HDD again, and see if it will boot from the HDD? 

How were you able to access the "boot drive" (is that the HDD?) and rollback the Windows 10 upgrade via the recovery options, if you were booting from the USB recovery disk?

I might need detailed steps, as I am a bit of a novice. :-)

Any further help you can provide is greatly appreciated! Many thanks!

Hi Yash, 

great the rollback worked.

My USB recovery stick booting the sata drive attached via usb gave me the option to repair the startup and to rollback the update.

In my case, I simply booted from the rolled back HDD attached back to the SATA without the recovery USB Stick and it booted just fine.

Later I removed the Lenovo backdoor stuff 1. from the security entry in the bios settings and later on on the windows directory. After that the upgrade to the 2004 update runs smoothly. Found this after reading thru the whole thread in here - sorry don‘t remember the name of the author.

Ciao, Bernd