diff --git a/reactos/base/applications/devmgmt/enumdevices.c b/reactos/base/applications/devmgmt/enumdevices.c
index 6dceb6061c1..099d50b8545 100644
--- a/reactos/base/applications/devmgmt/enumdevices.c
+++ b/reactos/base/applications/devmgmt/enumdevices.c
@@ -151,7 +151,9 @@ EnumDevices(INT index,
 
     if (!bRet)
     {
-        guids = HeapAlloc(GetProcessHeap(), 0, RequiredSize);
+        guids = HeapAlloc(GetProcessHeap(), 
+                          0, 
+                          RequiredSize * sizeof(GUID));
         if (guids == NULL)
             return -1;