EsentBackupDirectoryNotEmptyException "The backup directory is not emtpy"

Mar 9, 2015 at 8:49 AM
The follwing line of code is throwing EsentBackuDirectoryNotEmptyException:
Esent.Api.JetBackupInstance(instance, null, Esent.BackupGrbit.None, null);
However the documentation says that when destination is null the funtion will truncate the logs.

Is this a bug or I'm missing something?