Recovery Key on USB Drive Not Functioning

Hello:

I have an HP Elite book 8730w with TPM manager.

I have BitLocker-ed my local C-Drive.

I have copied the recovery key to a local USB drive.

When I boot my machine, it does not properly read the usb drive to gather the recovery key.

When the hard drive boots up, I can manually enter the recovery key and it boots juts fine.

What am I missing so that the usb can be properly read for the recovery key to function.  This would eliminate the need to manually enter the recovery key all the time.

Any thoughts or suggestions would be greatly appreciated.

Thanks again and have a great day,.

rafel