diff --git a/server/core/resources.dylan b/server/core/resources.dylan
index 967d7b0..aa3c503 100644
--- a/server/core/resources.dylan
+++ b/server/core/resources.dylan
@@ -92,11 +92,11 @@ define open generic respond-to-connect (resource :: <abstract-resource>, #key, #
 //
 define open generic default-content-type
     (resource :: <abstract-resource>)
- => (content-type :: type-union(<mime-type>, <string>));
-
+ => (content-type :: <byte-string>);
+ 
 define method default-content-type
     (resource :: <abstract-resource>)
- => (content-type :: <string>)
+ => (content-type :: <byte-string>)
   "application/octet-stream"
 end;
 
diff --git a/server/core/static-files.dylan b/server/core/static-files.dylan
index db800ca..cf9d92a 100644
--- a/server/core/static-files.dylan
+++ b/server/core/static-files.dylan
@@ -201,7 +201,8 @@ define method locator-media-type
   if (mtype)
     mtype
   else
-    let mtype :: <mime-type> = default-content-type(resource);
+    let mtype :: <mime-type>
+                 = string-to-mime-type(default-content-type(resource));
     make(<media-type>,
          type: mtype.mime-type,
          subtype: mtype.mime-subtype)
diff --git a/server/dsp/dsp.dylan b/server/dsp/dsp.dylan
index a880d97..aeb9ae3 100644
--- a/server/dsp/dsp.dylan
+++ b/server/dsp/dsp.dylan
@@ -59,7 +59,8 @@ define method make
 end;
 
 define method default-content-type
-    (resource :: <dylan-server-page>) => (content-type :: <string>)
+    (resource :: <dylan-server-page)
+ => (content-type :: <byte-string>)
   "text/html"
 end;