diff --git a/lib/taskjuggler/UTF8String.rb b/lib/taskjuggler/UTF8String.rb
index 3bf9e5ee..c113bbbe 100644
--- a/lib/taskjuggler/UTF8String.rb
+++ b/lib/taskjuggler/UTF8String.rb
@@ -127,6 +127,7 @@ def forceUTF8Encoding
     else
       begin
         # Ensure that the text has LF line ends and is UTF-8 encoded.
+        force_encoding("UTF-8")
         encode('UTF-8', :universal_newline => true)
       rescue
         # The encoding of the String is broken. Find the first broken line and