diff --git a/ArchiSteamFarm/ConcurrentEnumerator.cs b/ArchiSteamFarm/ConcurrentEnumerator.cs
index de993d74d..c091917ed 100644
--- a/ArchiSteamFarm/ConcurrentEnumerator.cs
+++ b/ArchiSteamFarm/ConcurrentEnumerator.cs
@@ -49,6 +49,11 @@ namespace ArchiSteamFarm {
 
 		public bool MoveNext() => Enumerator.MoveNext();
 		public void Reset() => Enumerator.Reset();
-		public void Dispose() => Lock.ExitReadLock();
+
+		public void Dispose() {
+			if (Lock != null) {
+				Lock.ExitReadLock();
+			}
+		}
 	}
 }