diff --git a/Errors.md b/Errors.md
index b0adf2d..23f7ea8 100644
--- a/Errors.md
+++ b/Errors.md
@@ -2,7 +2,7 @@ Some errors that can be thrown by SESSINIT property #4 and potentially other pla
 
 | Number | Name | Error message | Notes |
 | --- | --- | --- | --- |
-| 1 | NAK_BAD_USER | TBD | |
+| 1 | NAK_BAD_USER | Illegal user name.  Please enter a user name that is 2 to 16 alpha & numeric characters long. | |
 | 2 | NAK_MAX_ORDINARY | TBD | |
 | 3 | NAK_MAX_PRIORITY | TBD | |
 | 4 | | | AssertionError! (Crash?) |