Failed Download Handling - Error message in log

I got this error message from the “Scheduler” in the logs. I got my first download in Sabnzbd that failed since I started using Nzbdrone.

Error occurred while execution task NzbDrone.Core.Download.CheckForFailedDownloadCommand

System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary2.get_Item(TKey key) at NzbDrone.Core.Download.FailedDownloadService.<>c__DisplayClassc.<GetHistoryItems>b__b(History h) in m:\\buildAgent1\\work\\328d72309b633a8\\src\zbDrone.Core\\Download\\FailedDownloadService.cs:line 127 at System.Linq.Enumerable.WhereListIterator1.MoveNext()
at System.Collections.Generic.List1..ctor(IEnumerable1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable1 source) at NzbDrone.Core.Download.FailedDownloadService.GetHistoryItems(List1 grabbedHistory, String downloadClientId) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Download\FailedDownloadService.cs:line 127
at NzbDrone.Core.Download.FailedDownloadService.CheckHistory(List1 grabbedHistory, List1 failedHistory) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Download\FailedDownloadService.cs:line 100
at NzbDrone.Core.Download.FailedDownloadService.Execute(CheckForFailedDownloadCommand message) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Download\FailedDownloadService.cs:line 170
at NzbDrone.Core.Messaging.Commands.CommandExecutor.ExecuteCommand[TCommand](Command command) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Messaging\Commands\CommandExecutor.cs:line 117
at NzbDrone.Core.Messaging.Commands.CommandExecutor.PublishCommand[TCommand](TCommand command) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Messaging\Commands\CommandExecutor.cs:line 48
at CallSite.Target(Closure , CallSite , CommandExecutor , Object )
at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1)
at CallSite.Target(Closure , CallSite , CommandExecutor , Object )
at NzbDrone.Core.Messaging.Commands.CommandExecutor.PublishCommand(String commandTypeName) in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Messaging\Commands\CommandExecutor.cs:line 54
at NzbDrone.Core.Jobs.Scheduler.ExecuteCommands() in m:\buildAgent1\work\328d72309b633a8\src\zbDrone.Core\Jobs\Scheduler.cs:line 56

This is a bug that snuck through, there is a fix for it in develop already.

If you remove the failed download from SAB it should clear the error up. But it also means your SAB is not going to work with failed downloads properly because its not returning the ID required by drone to handle it.