BestCrypt shows the message "Error in opening Algorithm Driver Service" when its module (responsible for the encryption algorithm you used for the container) has been corrupted or does not exist.
Try to re-install the program this way:
- uninstall BestCrypt;
- REBOOT your computer;
- Install it again: https://www.jetico.com/download/bestcrypt-container-encryption
If the problem remains, perform a manual uninstallation.