Do not require encryption on removable drives
Microsoft does not document a supported Windows or BitLocker function for the `RDVRequireEncryption` DWORD value at this registry path.
since 0.9.8.11
Purpose
Show registry keys (1)
HKLM\SOFTWARE\Policies\Microsoft\FVE\RDVRequireEncryption
Microsoft does not document a supported Windows or BitLocker function for the RDVRequireEncryption DWORD value at this registry path. Consequently, no reliable direct effect on removable-drive encryption or write access can be attributed to the value 0.
In particular, this value does not have a documented ability to decrypt drives, turn off BitLocker, or guarantee write access to unencrypted removable drives.
Notes
Security
This value should not be treated as an established security policy. According to the published Microsoft documentation, it neither enforces encryption of removable drives nor makes unencrypted drives read-only.
Windows provides a separate policy named Deny write access to removable drives not protected by BitLocker for preventing writes to unencrypted removable data drives. If that policy is not in effect and no other access restriction applies, removable data drives can normally be mounted with read and write access regardless of whether they are protected by BitLocker.
Notes
RDVRequireEncryption must not be confused with the similarly named BitLocker CSP node RemovableDrivesRequireEncryption. Microsoft maps that CSP node to the Deny write access to removable drives not protected by BitLocker Group Policy setting and to the different registry value RDVDenyWriteAccess.
Windows documentation does not establish whether any third-party or vendor-specific software reads RDVRequireEncryption. Any such behavior would not be a documented Windows operating-system function.
Microsoft documentation
Microsoft Learn: Configure BitLocker
Microsoft Learn: BitLocker CSP