Fatal error System.Exception: Detected non-empty blocksets with no associated blocks!

I created a new backup from one hard drive to a hard drive in my little network. It started and run appr. an hour without issues. Then I rebooted my computer. But now I can’t start this backup any more. Errors see below.

Windows 7 64 bit, Duplicati - 2.0.3.7_canary_2018-06-17

2018-06-27 18:07:33 +02 - [Information-Duplicati.Library.Main.Controller-StartingOperation]: The operation Backup has started
2018-06-27 18:07:33 +02 - [Error-Duplicati.Library.Main.Operation.BackupHandler-FatalError]: Fatal error
System.Exception: Detected non-empty blocksets with no associated blocks!
   bei Duplicati.Library.Main.Database.LocalDatabase.VerifyConsistency(Int64 blocksize, Int64 hashsize, Boolean verifyfilelists, IDbTransaction transaction)
   bei Duplicati.Library.Main.Operation.Backup.BackupDatabase.<>c__DisplayClass31_0.<VerifyConsistencyAsync>b__0()
   bei Duplicati.Library.Main.Operation.Common.SingleRunner.<>c__DisplayClass6_0.<RunOnMain>b__0()
   bei Duplicati.Library.Main.Operation.Common.SingleRunner.<>c__DisplayClass5_0`1.<<DoRunOnMain>b__1>d.MoveNext()
--- Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde ---
   bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   bei Duplicati.Library.Main.Operation.BackupHandler.<RunAsync>d__19.MoveNext()

Repair of the database didn’t help:
[Information-Duplicati.Library.Main.Operation.RepairHandler-DatabaseIsSynchronized]: Destination and database are synchronized, not making any changes