@nsivov `clrdata` represents additional fields only for `clrClass` from component manifest file, which is for [.NET Framework-Based COM Component](https://learn.microsoft.com/en-us/dotnet/framework/interop/configure-net-fra...). The example code in this MR description is about calling COM dll from .NET application, so it uses `comClass` not `clrClass` in application manifest file. Besides, the [official doc](https://learn.microsoft.com/en-us/windows/win32/sbscs/manifest-file-schema) shows only `clrClass` has a name field, but `comClass` doesn't. And on [/dlls/ntdll/actctx.c line 4412](https://gitlab.winehq.org/wine/wine/-/blob/4dfbf077cf708e4bbffa8e086d78d6652...), `clrdata_offset` is set to zero if the name field is not set. [/dlls/ntdll/actctx.c line 4433](https://gitlab.winehq.org/wine/wine/-/blob/4dfbf077cf708e4bbffa8e086d78d6652...) checks `clrdata_offset` first, then set [/dlls/ntdll/actctx.c line 4449](https://gitlab.winehq.org/wine/wine/-/blob/4dfbf077cf708e4bbffa8e086d78d6652...) `clrdata_len`. So `clrdata_len` doesn't mean `ERROR_NOT_FOUND`. I've tested my .NET application working locally. I'm not sure how to add .NET C# code to the test pipeline here. -- https://gitlab.winehq.org/wine/wine/-/merge_requests/9632#note_124286