Exception while loading outlook message *.msg

[bytew0lf]

Describe the bug
While trying to load a Outlook Message I get the following exception:

System.TypeInitializationException: The type initializer for 'MsgReader.Rtf.Font' threw an exception. ---> System.ArgumentException: 'Windows-1252' is not a supported encoding name. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method. (Parameter 'name') at System.Text.EncodingTable.InternalGetCodePageFromName(String name) at System.Text.EncodingTable.GetCodePageFromName(String name) at System.Text.Encoding.GetEncoding(String name) at MsgReader.Rtf.Font..cctor() --- End of inner exception stack trace --- at MsgReader.Rtf.Font.get_DefaultEncoding() at MsgReader.Rtf.Font.EncodingFromCodePage(Int32 codePage) at MsgReader.Rtf.Document.DeEncapsulateHtmlFromRtf(String rtf) at MsgReader.Outlook.Storage.Message.get_BodyHtml() at MsgReader.Outlook.Storage.Message.LoadStorage(Storage storage) at MsgReader.Outlook.Storage..ctor(String storageFilePath, FileAccess fileAccess) at MsgReader.Outlook.Storage.Message..ctor(String msgfile, FileAccess fileAccess)

Another Exception with another exported E-Mail
System.NotSupportedException: No data is available for encoding 950. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method. at System.Text.Encoding.GetEncoding(Int32 codepage) at MsgReader.Outlook.Storage.get_InternetCodePage() at MsgReader.Outlook.Storage.get_MessageCodePage() at MsgReader.Outlook.Storage.Message.get_BodyRtf() at MsgReader.Outlook.Storage.Message.get_BodyHtml() at MsgReader.Outlook.Storage.Message.LoadStorage(Storage storage) at MsgReader.Outlook.Storage..ctor(String storageFilePath, FileAccess fileAccess) at MsgReader.Outlook.Storage.Message..ctor(String msgfile, FileAccess fileAccess) at CaseManager.Pages.Evidence.DetailsModel.BuildEmailPreviewHtml(String physicalPath, String extension)

This happens directly in this line
using var message = new MsgReader.Outlook.Storage.Message(physicalPath);

To Reproduce
Steps to reproduce the behavior:
Version: Microsoft® Outlook® for Microsoft 365 MSO (Version 2510 Build 16.0.19328.20266) 64-bit

1. Export a Message from Microsoft Outlook with Drag&Drop to the Filesystem
2. Try to load the message
3. See error

Expected behavior
The Outlook message should be loaded and decoded so its content can be used further in the program.

Desktop (please complete the following information):

• OS: Windows 11
• Browser Microsoft Edge
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[Sicos1977]

Are you using .net core(version 6 or higher)?

[bytew0lf]

Yes, dotnet 9, currently

[Sicos1977]

On net core you have to register the encodings yourself. 1252 ansi encoding for example is a Windows thing and because core is cross platform Microsoft dropped standard support for these.

[bytew0lf]

Ah, ok.
Thank you for the hint.

[bytew0lf]

Fix

For Future reference.
If dotnet 6 or higher is used.

Add System.Text.Encoding.CodePages nuget package to the Project
dotnet add package System.Text.Encoding.CodePages --version 9.0.11 or higher

Add the following lines at the top of Program.cs, before the first codeline after the using statements

// Register the CodePages encoding provider at application startup to enable using single and double byte encodings.
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);