Hi Surely. I'm Greg, 10 years awarded Windows MVP, specializing in Installation, Performance, Troubleshooting and Activation, here to help you.
If Bitlocker is enabled on your hard drive this may have been done at the factory, which the manufacturer's Support should tell you and provide what you need to know. Here is what Lenovo says about it:
BitLocker Information Page - Lenovo Support US
After BIOS update, got Bitlocker Recovery screen-English Community
Unexpected BitLocker recovery screen - ThinkPad, ideapad, ideacentre - Lenovo Support US
Lenovo Win10 Pro Bitlocker on by default-English Community
If done since then it should always store the Recovery key that unlocks it in your MS Account.
See here how to find the Recovery key for Bitlocker:
https://support.microsoft.com/en-us/help/402618...
Try removing or turning off Bitlocker by one of these methods:
https://www.repairwin.com/how-to-remove-bitlock...
https://www.tenforums.com/tutorials/37060-turn-...
https://www.tenforums.com/tutorials/36701-turn-...
Manual for managing Bitlocker:
https://www.windowscentral.com/how-use-bitlocke...
If you cannot find the key or turn off Bitlocker then you'll need to try to recover your data by one of the methods shown here:
https://www.howtogeek.com/263561/how-to-recover...
http://woshub.com/data-recovery-on-a-damaged-ha...
A few have tried this method successfully to Rescue files using bootable media so WIndows isn't running and has no say:
http://answers.microsoft.com/en-us/windows/wiki...
If nothing else works then wipe the drive to reinstall WIndows as shown here:
https://www.tenforums.com/tutorials/85819-erase...
http://answers.microsoft.com/en-us/windows/wiki...
Due to number of similar cases with files lost I would not use Bitlocker. Instead I would periodically drag my User folders to external USB which I keep unplugged to protect against ransomware. Then I would also have a secondary method using the cloud which is fire-, ransomware- and theft-proof:
You can drag 5gb for free into OneDrive app to store in the cloud or backup your Documents, Pictures and/or Desktop to capture real time changes using OneDrive Backup here: https://www.tenforums.com/tutorials/116029-turn...
If you install Google Drive Desktop, you can use their new Backup to choose User folders (Documents, Pictures, etc.) to sync up to 15g for free to their cloud: https://support.google.com/drive/answer/1083812...
If you want to report this to Microsoft use the Feedback Hub app in Start Menu where developers are tasked to process consumer feedback. They will not even see it here. This is a tech forums staffed mostly by volunteers trying to help others with your problems.
If you want to post back a Share link from your Feedback here others who see this thread can vote it up and add to it.
I hope this helps. Feel free to ask back any questions and keep me posted. I will keep working with you until it's resolved.
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