Hi there,
We observed multiple exceptions regarding msg files. I think, if the files are not actual msg files, it would make sense to throwing an exception telling that the documents are corrupted.
GroupDocs.Metadata.Exceptions.GroupDocsMetadataException: Image loading failed.
at GroupDocs.Metadata.Formats.Image.ImageRootPackage.xlvkm45y4n3jd8yancakp2dhnzf6x6gj\u0019\u0003\u0002()
at GroupDocs.Metadata.Formats.Image.ImageRootPackage.pfq4rhh3tnxzrhuh6z5nyqfxm3nvff3j\u0019\u0003\u0002()
at \u0005\u0010\u001B2.\u0005\u0010\u001B2\u0019\u0003\u0005\u0002(\u0002 \u0002)
at \u0008\u0002\u0010.\u000E\u001A\u000F\u0016\u0005\u0002()
at \u0003\u0016\u000F.\u0002(Int32 \u0002, \u0008\u001A\u000F \u0003)
System.NullReferenceException: Object reference not set to an instance of an object.
at nO.T3(MapiMessage d)\r\n at Aspose.Email.Mapi.MapiMessage.Y(Stream d, LoadOptions v)\r\n at Aspose.Email.Mapi.MapiMessage.Load(Stream stream, LoadOptions options)\r\n at \u000F\u0005\u0005.\u0002(Stream \u0002, LoadOptions \u0003)\r\n at \u0003\u000F\u0005.\u0002()\r\n at \u0003\u000F\u0005.\u0008\u0017\u0003\u0017\u0005\u0017\u0015\u0002()\r\n at GroupDocs.Parser.Parser.GetMetadata()\r\n at \u0003\u0016\u000F.\u0002(Document \u0002, \u0006\u001A\u000F \u0003, String \u0005)
System.Xml.XmlException: Data at the root level is invalid. Line 1, position 1. (if it’s not a valid msg file, an exception that it is corruped is probably better)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace()
at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
at \u0006\u0016\u001A\u0016.\u0002\u0016\u001A\u0016\u0003\u0016\u0008()
at \u0002\u0016\u001A\u0016.\u0002()
at \u0008\u001A\u0002.\u0002\u0010\u0003\u0003\u0016\u0002()
at \u0005\u0010\u0003.\u0002\u000F\u0003\u0003\u0016\u0002()
at GroupDocs.Metadata.Formats.Image.GifRootPackage.\u0002()
at GroupDocs.Metadata.Common.RootMetadataPackage.\u0002.\u0002()
at \u0008\u001A\u0018`2.\u0005.\u0002.MoveNext()
at \u0006\u0005\u0002.\u000E\u0018\u001B\u0003\u0016\u0008()
at \u0008\u001B\u001B.\u0002(Int32 \u0002, \u0006\u0018\u001B \u0008)
System.InvalidOperationException: The data of the attachment is empty
at Aspose.Email.Mapi.MapiAttachment.O(Stream d)
at \u0008\u000F\u0005.\u0002\u0018\u0003\u0017\u0005\u0017\u0015\u0002(ContainerItem \u0002)
at GroupDocs.Parser.Data.ContainerItem.OpenParser(LoadOptions loadOptions, ParserSettings parserSettings)
at \u000E\u0002\u0010.\u0008\u001A\u000F\u0016\u0005\u0002(\u0002\u0002\u000F \u0002, \u000F\u0018\u0010 \u0003, String \u0005)
at \u0003\u0016\u000F.\u0002(Int32 \u0002, \u0008\u001A\u000F \u0003)
at \u0003\u0016\u000F.\u0002(Document \u0002, \u0006\u001A\u000F \u0003, String \u0005)
System.IO.EndOfStreamException: Invalid bytes count
at \u0005\u001B\u0010.\u0002(String \u0002)
at \u000F\u001B\u0010.\u0002()
at GroupDocs.Metadata.Formats.Image.PngRootPackage.\u0002()
at \u0005\u0010\u001B`2.\u0002.MoveNext()
at \u0005\u0010\u001B`2.\u0005.\u0002.MoveNext()
at \u0008\u0002\u0010.\u000E\u001A\u000F\u0016\u0005\u0003()
at \u0003\u0016\u000F.\u0002(Int32 \u0002, \u0008\u001A\u000F \u0003)
GroupDocs.Metadata.Exceptions.XmpException: Invalid requested xml: <?xpacket begin=\"\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>
at \u0002\u0016\u001A\u0016…ctor(String \u0002)
at \u0006\u0016\u001A\u0016…ctor(String \u0002)
at \u000E\u000F\u000F.\u0002()
at GroupDocs.Metadata.Formats.Image.PngRootPackage.\u0002()
at GroupDocs.Metadata.Common.RootMetadataPackage.\u0002.\u0002()
at \u0008\u001A\u0018`2.\u0005.\u0002.MoveNext()
at \u0006\u0005\u0002.\u000E\u0018\u001B\u0003\u0016\u0008()
at \u0008\u001B\u001B.\u0002(Int32 \u0002, \u0006\u0018\u001B \u0008)
System.InvalidOperationException: Mail message is not signed
at Aspose.Email.MailMessage.RemoveSignature()
at Aspose.Email.Mapi.MapiMessage.Y(Stream d, LoadOptions v)
at \u000F\u0005\u0005.\u0002(Stream \u0002, LoadOptions \u0003)
at \u0003\u000F\u0005.\u0008\u0017\u0003\u0017\u0005\u0017\u0015\u0002()
at GroupDocs.Parser.Parser.GetMetadata()
at \u0003\u0016\u000F.\u0002(Document \u0002, \u0006\u001A\u000F \u0003, String \u0005)
GroupDocs.Metadata.Exceptions.InvalidFormatException: Unknown block label
at \u000E\u0010\u0010.\u0002()
at \u0005\u0015\u0010.\u0008\u0017\u0005\u0019\u0003\u0002()
at \u000E\u0017\u0005.\u0006\u001B\u0003\u0019\u0003\u0002()
at GroupDocs.Metadata.Formats.Image.GifRootPackage.\u0002()
at GroupDocs.Metadata.Common.RootMetadataPackage.\u0002.\u0002()
at \u0005\u0010\u001B`2.\u0002.MoveNext()
at \u0005\u0010\u001B`2.\u0005.\u0002.MoveNext()
at \u0008\u0002\u0010.\u000E\u001A\u000F\u0016\u0005\u0003()
at \u0003\u0016\u000F.\u0002(Int32 \u0002, \u0008\u001A\u000F \u0003)