bootbootcampfirmware-passwordpassword
I installed Windows 10 via Boot Camp couple of months ago and it worked normally. Today I tried to boot into Windows, but a password form pops up (firmware protection form). Booting into macOS without holding option key works OK.
I have tried entering the passwords for an admin account, my Apple ID, and iCloud, as well as booting into local and network recovery modes. Nothing worked.
I don't have "Find My Mac" installed or a recovery partition.
Where I can find this password or bypass it?
If you get a copy of Paragon NTFS for Mac you can do a disk repair for NTFS volumes. The software has a 10 day trial and a license is about $20. NTFS for Mac also serves as a driver for full access to NTFS volumes which is superior to the limited Read only access of NTFS volumes built into Macs. If you are a regular user of both Mac and Windows its worth the investment.
Once installed the program is accessible from System Preferences. For the problem described above you need to first unmount the volumes "System Reserve" and "BootCamp". Then remount the volumes and run verify on each volume.
You could try to fix the MBR Table.
I would recommend by using a Linux LiveCD or the rEFInd CD http://www.rodsbooks.com/refind/index.html
Alternatively, rEFInd can be installed on OS X so you also get a Partition Manager Tool. I used this tool once to fix my broken MBR Table.
You can find the install instructions for OS X here: rEFInd Install OS X
I hope this helps.
Best Answer
This is normal, and is likely because you enabled a Firmware Password while under Recovery Mode. Having a firmware password prevents your computer from booting from other boot partitions besides your main MacOS partition without your permission.
For more reference, view the relevant Apple Support page here.