diff --git a/library/error.c b/library/error.c
index eef05f4..9980a91 100644
--- a/library/error.c
+++ b/library/error.c
@@ -590,6 +590,8 @@
         snprintf( buf, buflen, "ENTROPY - No more sources can be added" );
     if( use_ret == -(POLARSSL_ERR_ENTROPY_NO_SOURCES_DEFINED) )
         snprintf( buf, buflen, "ENTROPY - No sources have been added to poll" );
+    if( use_ret == -(POLARSSL_ERR_ENTROPY_FILE_IO_ERROR) )
+        snprintf( buf, buflen, "ENTROPY - Read/write error in file" );
 #endif /* POLARSSL_ENTROPY_C */
 
 #if defined(POLARSSL_GCM_C)