When attempting to upload one or more PDF's that is missing a title, author, or subject; an unhandled exception is being thrown after the PDF's are copied into the top level of the Upload folder. Normally, when a PDF is missing a title, author, or subject; PDFKeeper is supposed to move the PDF to the UploadRejected folder. Unfortunately, because PDFKeeper has crashed, the PDF's will remain in the Upload folder causing the same unhandled exception to be thrown when PDFKeeper attempts to upload again after restarting.

Both PDFKeeper v9.0.0 and v9.1.0 are impacted by this bug.

The stack trace of exception that is logged to PDFKeeper.log
System.NullReferenceException: Object reference not set to an instance of an object.
at PDFKeeper.Core.Rules.PdfMetadataRule.CheckForViolation()
at PDFKeeper.Core.FileIO.PDF.PdfUploader.StagePdfFilesInUploadDirectory()
at PDFKeeper.Core.Presenters.MainPresenter.ExecuteUpload()
at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at PDFKeeper.Presentation.MainView.VB$StateMachine_491_UploadTimer_Tick.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()

To prevent PDFKeeper from crashing again after restarting; move the PDF's out of C:\Users\your_username\AppData\Roaming\Robert F. Frasca\PDFKeeper\Upload and then restart PDFKeeper.