diff --git a/reactos/include/psdk/wincred.h b/reactos/include/psdk/wincred.h
index 115e5810bbb..02bd1d8e7b4 100644
--- a/reactos/include/psdk/wincred.h
+++ b/reactos/include/psdk/wincred.h
@@ -184,6 +184,7 @@ typedef struct _BINARY_BLOB_CREDENTIAL_INFO
 #define CRED_MAX_ATTRIBUTES                 64
 
 #define CRED_MAX_BLOB_SIZE                  512
+#define CRED_MAX_CREDENTIAL_BLOB_SIZE       (5 * CRED_MAX_BLOB_SIZE)
 
 #define CREDUI_MAX_MESSAGE_LENGTH 32767
 #define CREDUI_MAX_CAPTION_LENGTH 128