diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 2f5ff604df..e0837c6aa0 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -27,6 +27,10 @@ declare var module: any;
 declare var process: any;
 declare var global: any;
 
+enum SystemError {
+    UnsupportedFileEncoding
+}
+
 var sys: System = (function () {
 
     function getWScriptSystem(): System {
@@ -68,7 +72,9 @@ var sys: System = (function () {
                 return fileStream.ReadText();
             }
             catch (e) {
-                throw e.number === -2147024809 ? new Error(ts.Diagnostics.Unsupported_file_encoding.key) : e;
+                if (e.number === -2147024809) {
+                    e.systemError = SystemError.UnsupportedFileEncoding;
+                }
             }
             finally {
                 fileStream.Close();
diff --git a/src/compiler/tsc.ts b/src/compiler/tsc.ts
index c8cccd2da1..e6e48e32e4 100644
--- a/src/compiler/tsc.ts
+++ b/src/compiler/tsc.ts
@@ -71,6 +71,15 @@ module ts {
 
         return true;
     }
+    
+    function getSystemErrorMessage(e: SystemError): string {
+        switch (e) {
+            case SystemError.UnsupportedFileEncoding:
+                return getDiagnosticText(Diagnostics.Unsupported_file_encoding);
+            default:
+                Debug.assert("Unreachable code in 'getSystemErrorMessage'");
+        }
+    }
 
     function countLines(program: Program): number {
         var count = 0;
@@ -149,7 +158,7 @@ module ts {
             }
             catch (e) {
                 if (onError) {
-                    onError(e.message);
+                    onError(e.systemError ? getSystemErrorMessage(e.systemError) : e.message);
                 }
                 text = "";
             }