diff --git a/src/answer.sh b/src/answer.sh
index 95925038..bd314f13 100644
--- a/src/answer.sh
+++ b/src/answer.sh
@@ -946,7 +946,8 @@ validateLegacyUsername() {
   fi
 
   case "$value" in
-    *'"'* | *'/'* | *\\* | *'['* | *']'* | *':'* | *';'* | *'|'* | *'='* | *','* | *'+'* | *'*'* | *'?'* | *'<'* | *'>'* )
+    *'"'* | *'/'* | *\\* | *'['* | *']'* | *':'* | *';'* | *'|'* | *'='* | \
+    *','* | *'+'* | *'*'* | *'?'* | *'<'* | *'>'* | *'%'* )
       error "The USERNAME variable contains unsupported characters$suffix!"
       return 1 ;;
   esac
@@ -961,10 +962,14 @@ validateLegacyUsername() {
     return 1
   fi
 
-  if [[ "${value^^}" == "GUEST" ]]; then
-    error "The USERNAME value \"$value\" is reserved for a built-in Windows account$suffix!"
-    return 1
-  fi
+  case "${value^^}" in
+    "NONE" )
+      error "The USERNAME value \"NONE\" is reserved by Windows$suffix!"
+      return 1 ;;
+    "ADMINISTRATOR" | "GUEST" | "DEFAULTACCOUNT" | "WDAGUTILITYACCOUNT" | "WSIACCOUNT" )
+      error "The USERNAME value \"$value\" is reserved for a built-in Windows account$suffix!"
+      return 1 ;;
+  esac
 
   return 0
 }