anchor.diff:      /// Platform name set on Build tab of project settings (or through platform parameter in appveyor.yml).
       static member Platform = environVar "PLATFORM"
   
  -    /// Configuration name set on Build tab of project settings (or through configuration parameter in appveyor.yml).  
  +    /// Configuration name set on Build tab of project settings (or through configuration parameter in appveyor.yml).
       static member Configuration  = environVar "CONFIGURATION"
   
       /// The job name
       static member JobName = environVar "APPVEYOR_JOB_NAME"
  -    
  -let private sendToAppVeyor args = 
  -    ExecProcess (fun info -> 
  +
  +let private sendToAppVeyor args =
  +    ExecProcess (fun info ->
           info.FileName <- "appveyor"
           info.Arguments <- args) (System.TimeSpan.MaxValue)
       |> ignore
   
  -let private add msg category = 
  -    sprintf "AddMessage %s -Category %s" (quoteIfNeeded msg) (quoteIfNeeded category) |> sendToAppVeyor
  +let private add msg category =
  +    if not <| isNullOrEmpty msg then
  +        let enableProcessTracingPreviousValue = enableProcessTracing
  +        enableProcessTracing <- false
  +        sprintf "AddMessage %s -Category %s" (quoteIfNeeded msg) (quoteIfNeeded category) |> sendToAppVeyor
  +        enableProcessTracing <- enableProcessTracingPreviousValue
   let private addNoCategory msg = sprintf "AddMessage %s" (quoteIfNeeded msg) |> sendToAppVeyor
   
   // Add trace listener to track messages
  -if buildServer = BuildServer.AppVeyor then 
  +if buildServer = BuildServer.AppVeyor then
       { new ITraceListener with
  -          member this.Write msg = 
  +          member this.Write msg =
                 match msg with
                 | ErrorMessage x -> add x "Error"
                 | ImportantMessage x -> add x "Warning"
                 | LogMessage(x, _) -> add x "Information"
  -              | TraceMessage(x, _) -> 
  +              | TraceMessage(x, _) ->
                     if not enableProcessTracing then addNoCategory x
                 | StartMessage | FinishedMessage | OpenTag(_, _) | CloseTag _ -> () }
       |> listeners.Add
  
positive.code:         |> sendToAppVeyor
  
  /// Update build version. This must be unique for the current project.
  let UpdateBuildVersion version = 
      UpdateBuild (fun p -> { p with Version = version })
  
negative.code: 
  /// AppVeyor parameters for update build as [described](https://www.appveyor.com/docs/build-worker-api/#update-build-details)
  [<CLIMutable>]
  type UpdateBuildParams =
      { /// Build version; must be unique for the current project
        Version : string
        /// Commit message
  