diff --git a/src/mkvinfo.cpp b/src/mkvinfo.cpp
index 10f217401..6db955ad6 100644
--- a/src/mkvinfo.cpp
+++ b/src/mkvinfo.cpp
@@ -1413,6 +1413,12 @@ bool process_file(const char *file_name) {
                 f_data.ReadData(es->I_O());
                 show_element(l3, 3, "File data, size: %u", f_data.GetSize());
 
+              } else if (EbmlId(*l3) == KaxFileUID::ClassInfos.GlobalId) {
+                KaxFileUID &f_uid =
+                  *static_cast<KaxFileUID *>(l3);
+                f_uid.ReadData(es->I_O());
+                show_element(l3, 3, "File UID: %u", uint32(f_uid));
+
               } else if (!is_ebmlvoid(l3, 3, upper_lvl_el))
                 show_unknown_element(l3, 3);
 
diff --git a/src/mkvmerge.cpp b/src/mkvmerge.cpp
index 4b97d9fa4..edabcb677 100644
--- a/src/mkvmerge.cpp
+++ b/src/mkvmerge.cpp
@@ -857,8 +857,10 @@ static void render_attachments(IOCallback *out) {
         die("Internal error: *name == 0 on %d.", __LINE__);
 
       *static_cast<EbmlUnicodeString *>
-        (&GetChild<KaxFileName>(*kax_a)) =
-        cstr_to_UTFstring(name);
+        (&GetChild<KaxFileName>(*kax_a)) = cstr_to_UTFstring(name);
+
+      *static_cast<EbmlUInteger *>
+        (&GetChild<KaxFileUID>(*kax_a)) = create_unique_uint32();
 
       try {
         io = new mm_io_c(attch->name, MODE_READ);