diff --git a/reactos/ntoskrnl/io/iomgr/file.c b/reactos/ntoskrnl/io/iomgr/file.c
index 789f0dd9e22..060a0fb0c59 100644
--- a/reactos/ntoskrnl/io/iomgr/file.c
+++ b/reactos/ntoskrnl/io/iomgr/file.c
@@ -1405,7 +1405,7 @@ IopSetDeviceSecurityDescriptor(IN PDEVICE_OBJECT DeviceObject,
         }
 
         KeEnterCriticalRegion();
-        ExAcquireResourceSharedLite(&IopSecurityResource, TRUE);
+        ExAcquireResourceExclusiveLite(&IopSecurityResource, TRUE);
         /* Check if someone changed it in our back */
         if (DeviceObject->SecurityDescriptor == OldSecurityDescriptor)
         {