The key can not be generated or created once if it is lost .
If you are unable to locate the BitLocker recovery key and can't revert any configuration change that might have caused it to be required, you'll need to reset your device using one of the Windows recovery options. Resetting your device will remove all of your files.
The 48-digit BitLocker recovery key is automatically generated by the Windows system when you enable the BitLocker function for the first time. It is usually stored in a TXT file.
Hope this resolves your Query !!
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