McAfee does not obtain, cache, or retain any customer keys and cannot unlock drives. All recoveries would be based upon the settings in place at the time of initialization.
There are two types of encrypted USB drives. The first is disks that have been encrypted using McAfee File and Removable Media (FRP) (formally Endpoint Encryption for Files and Folders). This type of encryption allows for 3 types of recovery: Password, Certificate, and Recovery Key. You will need to utilize FRP to perform a recovery on the disk and utilize either the password, certificate, or key set by the policy that encrypted the disk. If none of these are available, no recovery is possible.
If the disk is a McAfee branded self encrypting flash drive or hard disk, ePO would need to be utilized to perform the recovery or on the system in which the disk was initialized if you had self rescue enabled at the time of initialization. These disks have gone end of life / end of support.