diff --git a/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Base.pas b/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Base.pas
index 692fba5fc5..3fa77fa3c7 100644
--- a/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Base.pas
+++ b/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Base.pas
@@ -58,7 +58,11 @@ begin
     Exit;
   end;
 
-  AResponseInfo.ContentType :=  AResponseInfo.HTTPServer.MIMETable.GetFileMIMEType(AFileName);
+  if AResponseInfo.ContentType = '' then
+  begin
+    AResponseInfo.HTTPServer.MIMETable.LoadTypesFromOS := False;
+    AResponseInfo.ContentType := AResponseInfo.HTTPServer.MIMETable.GetFileMIMEType(AFileName);
+  end;
   AResponseInfo.CharSet := 'UTF-8';
   AResponseInfo.ContentLength := FileSizeByName(AFileName);
 //AResponseInfo.LastModified := GetFileDate(doc);
diff --git a/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Debugger.pas b/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Debugger.pas
index 9ad35f5bc5..fbdc2ba16b 100644
--- a/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Debugger.pas
+++ b/windows/src/developer/TIKE/http/Keyman.Developer.System.HttpServer.Debugger.pas
@@ -652,6 +652,7 @@ begin
       Delete(doc, 1, 6);
 
       // Models always expire immediately
+      AResponseInfo.ContentType := 'application/javascript';
       AResponseInfo.Expires := EncodeDate(1990, 1, 1);   // I4037
       AResponseInfo.CacheControl := 'no-cache, no-store';   // I4037
       AResponseInfo.LastModified := Now;   // I4037
@@ -686,7 +687,11 @@ begin
 
     // Serve the file
 
-    AResponseInfo.ContentType :=  AResponseInfo.HTTPServer.MIMETable.GetFileMIMEType(doc);
+    if AResponseInfo.ContentType = '' then
+    begin
+      AResponseInfo.HTTPServer.MIMETable.LoadTypesFromOS := False;
+      AResponseInfo.ContentType :=  AResponseInfo.HTTPServer.MIMETable.GetFileMIMEType(doc);
+    end;
     AResponseInfo.CharSet := 'UTF-8';
     AResponseInfo.ContentLength := FileSizeByName(doc);
   //AResponseInfo.LastModified := GetFileDate(doc);