diff --git a/profile/pref-migrator/src/nsPrefMigration.cpp b/profile/pref-migrator/src/nsPrefMigration.cpp
index 8339c757ce81..4441b8e662d8 100644
--- a/profile/pref-migrator/src/nsPrefMigration.cpp
+++ b/profile/pref-migrator/src/nsPrefMigration.cpp
@@ -1756,6 +1756,7 @@ nsPrefMigration::Rename4xFileAfterMigration(nsIFileSpec * profilePath, const cha
   return rv;
 }
 
+#ifdef NEED_TO_COPY_AND_RENAME_NEWSRC_FILES
 nsresult
 nsPrefMigration::GetPremigratedFilePref(const char *pref_name, nsIFileSpec **path)
 {
@@ -1772,6 +1773,8 @@ nsPrefMigration::GetPremigratedFilePref(const char *pref_name, nsIFileSpec **pat
         return rv;
 }
 
+#endif /* NEED_TO_COPY_AND_RENAME_NEWSRC_FILES */
+
 nsresult 
 nsPrefMigration::SetPremigratedFilePref(const char *pref_name, nsIFileSpec *path)
 {