diff --git a/Wabbajack.Common/Utils.cs b/Wabbajack.Common/Utils.cs
index 275243d1..c78c26a2 100644
--- a/Wabbajack.Common/Utils.cs
+++ b/Wabbajack.Common/Utils.cs
@@ -928,5 +928,12 @@ namespace Wabbajack.Common
             var decoded = ProtectedData.Unprotect(bytes, Encoding.UTF8.GetBytes(key), DataProtectionScope.LocalMachine);
             return Encoding.UTF8.GetString(decoded).FromJSONString<T>();
         }
+
+        public static bool IsInPath(this string path, string parent)
+        {
+            return path.ToLower().TrimEnd('\\').StartsWith(parent.ToLower().TrimEnd('\\') + "\\");
+        }
+
+
     }
 }
diff --git a/Wabbajack.Lib/AInstaller.cs b/Wabbajack.Lib/AInstaller.cs
index b122c472..a40f81e2 100644
--- a/Wabbajack.Lib/AInstaller.cs
+++ b/Wabbajack.Lib/AInstaller.cs
@@ -348,10 +348,8 @@ namespace Wabbajack.Lib
                 {
                     var relative_to = f.RelativeTo(OutputFolder);
                     Utils.Status($"Checking if modlist file {relative_to}");
-                    if (indexed.ContainsKey(relative_to) || f.StartsWith(DownloadFolder + Path.DirectorySeparator))
-                    {
+                    if (indexed.ContainsKey(relative_to) || f.IsInPath(DownloadFolder))
                         return;
-                    }
 
                     Utils.Log($"Deleting {relative_to} it's not part of this modlist");
                     File.Delete(f);
diff --git a/Wabbajack.Test/UtilsTests.cs b/Wabbajack.Test/UtilsTests.cs
new file mode 100644
index 00000000..cd913a43
--- /dev/null
+++ b/Wabbajack.Test/UtilsTests.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Wabbajack.Common;
+
+namespace Wabbajack.Test
+{
+    [TestClass]
+    public class UtilsTests
+    {
+        [TestMethod]
+        public void IsInPathTests()
+        {
+            Assert.IsTrue("c:\\foo\\bar.exe".IsInPath("c:\\foo"));
+            Assert.IsFalse("c:\\foo\\bar.exe".IsInPath("c:\\fo"));
+            Assert.IsTrue("c:\\Foo\\bar.exe".IsInPath("c:\\foo"));
+            Assert.IsTrue("c:\\foo\\bar.exe".IsInPath("c:\\Foo"));
+            Assert.IsTrue("c:\\foo\\bar.exe".IsInPath("c:\\fOo"));
+            Assert.IsTrue("c:\\foo\\bar.exe".IsInPath("c:\\foo\\"));
+            Assert.IsTrue("c:\\foo\\bar\\".IsInPath("c:\\foo\\"));
+        }
+    }
+}
diff --git a/Wabbajack.Test/Wabbajack.Test.csproj b/Wabbajack.Test/Wabbajack.Test.csproj
index d95eeaa3..3bbe3d94 100644
--- a/Wabbajack.Test/Wabbajack.Test.csproj
+++ b/Wabbajack.Test/Wabbajack.Test.csproj
@@ -112,6 +112,7 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ContentRightsManagementTests.cs" />
     <Compile Include="CompilationStackTests.cs" />
+    <Compile Include="UtilsTests.cs" />
     <Compile Include="VortexTests.cs" />
     <Compile Include="WebAutomationTests.cs" />
     <Compile Include="zEditIntegrationTests.cs" />