diff --git a/lib/create.c b/lib/create.c
index b660d11e5..72b4632c8 100644
--- a/lib/create.c
+++ b/lib/create.c
@@ -241,6 +241,14 @@ is_power_of_2 (unsigned v)
   return v && ((v & (v - 1)) == 0);
 }
 
+static void
+read_all (guestfs_h *g, void *retv, const char *buf, size_t len)
+{
+  char **ret = retv;
+
+  *ret = safe_strndup (g, buf, len);
+}
+
 /**
  * Check for valid backing format.  Allow any C<^[[:alnum]]+$>
  * (in C locale), but limit the length to something reasonable.
@@ -256,6 +264,7 @@ disk_create_qcow2 (guestfs_h *g, const char *filename, int64_t size,
 {
   const char *backingformat = NULL;
   CLEANUP_FREE char *backingformat_free = NULL;
+  CLEANUP_FREE char *cmd_stdout = NULL;
   const char *preallocation = NULL;
   const char *compat = NULL;
   int clustersize = -1;
@@ -351,10 +360,16 @@ disk_create_qcow2 (guestfs_h *g, const char *filename, int64_t size,
   if (size >= 0)
     guestfs_int_cmd_add_arg_format (cmd, "%" PRIi64, size);
 
+  guestfs_int_cmd_clear_capture_errors (cmd);
+  guestfs_int_cmd_set_stderr_to_stdout (cmd);
+  guestfs_int_cmd_set_stdout_callback (cmd, read_all, &cmd_stdout,
+                                       CMD_STDOUT_FLAG_WHOLE_BUFFER);
   r = guestfs_int_cmd_run (cmd);
   if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) {
-    guestfs_int_external_command_failed (g, r, "qemu-img", filename);
+    guestfs_int_external_command_failed (g, r, "qemu-img", cmd_stdout);
     return -1;
+  } else {
+    debug (g, cmd_stdout);
   }
 
   return 0;