Hi Simon,

since I had the same problem as you have, I needed to find a solution for the problem.

Happily I succeeded.

The following code is written in .Net6 using the SoapFormatter Nugget Version 1.1.9

		private void convertUltraGridLayoutFromXmlToBinary(string xmlFilename, string binaryFilename)
		{
			UltraGridLayout layout;
			#region load the UltraGrid from XML
			FileStream fileStream = new FileStream(xmlFilename, FileMode.Open, FileAccess.Read);
			try
			{
				SoapFormatter soapFormatter = new SoapFormatter(null, new StreamingContext(StreamingContextStates.Persistence))
				{
					AssemblyFormat = FormatterAssemblyStyle.Simple,
					Binder = new Infragistics.Win.UltraWinGrid.Serialization.Binder()
				};
				layout = soapFormatter.Deserialize(fileStream) as UltraGridLayout;
			}
			finally
			{
				fileStream.Close();
			}
			#endregion

			#region save the UltraGrid to binary
			fileStream = new FileStream(binaryFilename, FileMode.OpenOrCreate, FileAccess.Write);
			try
			{
				BinaryFormatter binaryFormatter = new BinaryFormatter(null, new StreamingContext(StreamingContextStates.Persistence))
				{
					AssemblyFormat = FormatterAssemblyStyle.Simple
				};
				if (layout != null)
				{
#pragma warning disable SYSLIB0011
					binaryFormatter.Serialize(fileStream, layout);
#pragma warning restore SYSLIB0011
				}
			}
			finally
			{
				fileStream.Close();
			}
			#endregion
		}

Just execute this method before you do DisplayLayout.Load(...), which was LoadFromXML(...) before.

Hope that helps you, too.