diff --git a/src/LfMerge.Core/Settings/LfMergeSettings.cs b/src/LfMerge.Core/Settings/LfMergeSettings.cs
index 2b84d4b9..4177551c 100644
--- a/src/LfMerge.Core/Settings/LfMergeSettings.cs
+++ b/src/LfMerge.Core/Settings/LfMergeSettings.cs
@@ -38,7 +38,7 @@ public string MongoHostname {
 
 		private string _mongoPort;
 		public string MongoPort {
-			get => Environment.GetEnvironmentVariable(MagicStrings.SettingsEnvVar_MongoPort) ?? DefaultLfMergeSettings.MongoPort.ToString();
+			get => _mongoPort ?? Environment.GetEnvironmentVariable(MagicStrings.SettingsEnvVar_MongoPort) ?? DefaultLfMergeSettings.MongoPort.ToString();
 			set => _mongoPort = value;
 		}