diff --git a/dll/win32/advapi32/reg/reg.c b/dll/win32/advapi32/reg/reg.c
index 284731628b1..1e06f67a919 100644
--- a/dll/win32/advapi32/reg/reg.c
+++ b/dll/win32/advapi32/reg/reg.c
@@ -546,6 +546,7 @@ RegpCopyTree(IN HKEY hKeySrc,
                     if (Buffer != NULL)
                     {
                         Info.Buffer = Buffer;
+                        BufferSize = BufferSizeRequired;
                         /* try again */
                     }
                     else
@@ -672,6 +673,7 @@ RegpCopyTree(IN HKEY hKeySrc,
                     if (Buffer != NULL)
                     {
                         Info.Buffer = Buffer;
+                        BufferSize = BufferSizeRequired;
                         /* try again */
                     }
                     else