The message 'Undefined Key Generator Error ' or "Key generator ID is not  defined" appears in the following cases:

1. When some module in BestCrypt Key Generator has been corrupted.

2. If an older version of BestCrypt is used to open a container created with SHA-256 key generator (available in version 7.12 or later).

3. If an older version of BestCrypt is used to open a container created with KG-Ghost key generator (available in version 8.0 or later).

Please note that containers created by an older version are always compatible with future versions, but not vice versa.

Installing the newest version will help to solve this problem.