Windows guides
How to Rebuild the BCD in Windows 10 or Windows 8.1
Repair Boot Configuration Data from Windows Recovery Environment, using Startup Repair first and Bootrec or BCDBoot only when needed.
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rebuild bcd
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Troubleshooting
Fix UNMOUNTABLE_BOOT_VOLUME (0x000000ED) in Windows 7 — Historical Guide
Historical Windows 7 recovery guide for the UNMOUNTABLE_BOOT_VOLUME 0xED blue-screen error, using file-system checks, Startup Repair, and hardware diagnostics.