Error 0x8031004B

Value: -2144272309 | 0x8031004B | 2150694987

What does it mean ?

FVE_E_FS_MOUNTED  
The drive cannot be locked when the drive is in use.
Value: 75 | 0x004B | 0b0000000001001011

Where does it come from ?

FACILITY_FVE  
Full volume encryption
Value: 49 | 0x031 | 0b00110001

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