From 395f23e1d3f50015b0dfe62481ed324e3b1e4025 Mon Sep 17 00:00:00 2001
From: Jeremy Stretch <stretch@packetlife.net>
Date: Thu, 2 Jan 2020 09:47:02 -0500
Subject: [PATCH] Fix for #3822

---
 netbox/dcim/models.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/netbox/dcim/models.py b/netbox/dcim/models.py
index 6d3de7c0b..8f95fa19a 100644
--- a/netbox/dcim/models.py
+++ b/netbox/dcim/models.py
@@ -2597,7 +2597,7 @@ class DeviceBay(ComponentModel):
         # Check that the installed device is not already installed elsewhere
         if self.installed_device:
             current_bay = DeviceBay.objects.filter(installed_device=self.installed_device).first()
-            if current_bay != self:
+            if current_bay and current_bay != self:
                 raise ValidationError({
                     'installed_device': "Cannot install the specified device; device is already installed in {}".format(
                         current_bay