After uploading a map, I got the following error:
Unexpected Runtime Error
Something went wrong:
The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int64' for method 'System.Web.Mvc.ActionResult Track_Upload_Multi_Manage(Int64)' in 'TmExchange.Controllers.MappackController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters
Apparently the track did upload correctly. I had to delete a duplicate upload after trying again.