diff --git a/dix/devices.c b/dix/devices.c
index 1516147a57..c4b2587b12 100644
--- a/dix/devices.c
+++ b/dix/devices.c
@@ -536,6 +536,7 @@ DisableDevice(DeviceIntPtr dev, BOOL sendevent)
     }
 
     RecalculateMasterButtons(dev);
+    dev->master = NULL;
 
     return TRUE;
 }