diff -r ae4ab6efa941 -r b0076c5c7eec src.lock_maildirsize
--- a/src.lock_maildirsize	Sat Feb 26 22:52:11 2011 +0100
+++ b/src.lock_maildirsize	Tue Mar 08 11:11:21 2011 +0100
@@ -3,7 +3,7 @@
 
 diff -r 64ab3b627703 src/transports/appendfile.c
 --- a/src/transports/appendfile.c	Thu Feb 24 20:29:56 2011 +0100
-+++ b/src/transports/appendfile.c	Sat Feb 26 22:51:42 2011 +0100
++++ b/src/transports/appendfile.c	Sun Feb 27 21:51:22 2011 +0100
 @@ -13,6 +13,7 @@
  
  #ifdef SUPPORT_MAILDIR
@@ -94,16 +94,20 @@
        if (mailbox_size < 0) mailbox_size = size;
        if (mailbox_filecount < 0) mailbox_filecount = filecount;
        }
-@@ -3125,6 +3150,8 @@
+@@ -3125,6 +3150,12 @@
        uschar *renamename = newname;
        fd = -1;
  
-+			if (lockfd >= 0) hs12_lock(lockfd, F_RDLCK, "for delivery");
++			/* we could get a timeout here, but we don't check for it. Thus it *may*
++			happen, that we deliver during an active RECALC process. Shit happens and it
++			will cause the RECALC to discard its result... */
++
++			if (lockfd >= 0) hs12_lock(lockfd, F_RDLCK, "for renaming temporary file");
 +
        DEBUG(D_transport) debug_printf("renaming temporary file\n");
  
        /* If there is no rename name set, we are in a non-maildir, non-mailstore
-@@ -3245,6 +3272,7 @@
+@@ -3245,6 +3276,7 @@
            filename = dataname = NULL;   /* Prevents attempt to unlink at end */
            }
          }        /* maildir or mailstore */
@@ -111,7 +115,7 @@
        }          /* successful write + close */
      }            /* isdirectory */
    }              /* write success */
-@@ -3280,6 +3308,11 @@
+@@ -3280,6 +3312,11 @@
  detected, in order to get the file closed and the lock file tidied away. */
  
  RETURN:
@@ -125,7 +129,7 @@
  if (mbx_lockfd >= 0)
 diff -r 64ab3b627703 src/transports/appendfile.h
 --- a/src/transports/appendfile.h	Thu Feb 24 20:29:56 2011 +0100
-+++ b/src/transports/appendfile.h	Sat Feb 26 22:51:42 2011 +0100
++++ b/src/transports/appendfile.h	Sun Feb 27 21:51:22 2011 +0100
 @@ -95,5 +95,8 @@
  /* Function that is shared with tf_maildir.c */
  
@@ -137,7 +141,7 @@
  /* End of transports/appendfile.h */
 diff -r 64ab3b627703 src/transports/tf_maildir.c
 --- a/src/transports/tf_maildir.c	Thu Feb 24 20:29:56 2011 +0100
-+++ b/src/transports/tf_maildir.c	Sat Feb 26 22:51:42 2011 +0100
++++ b/src/transports/tf_maildir.c	Sun Feb 27 21:51:22 2011 +0100
 @@ -367,13 +367,16 @@
  
  Returns:           >=0  a file descriptor for an open maildirsize file
@@ -246,7 +250,7 @@
  *returned_size = size;
 diff -r 64ab3b627703 src/transports/tf_maildir.h
 --- a/src/transports/tf_maildir.h	Thu Feb 24 20:29:56 2011 +0100
-+++ b/src/transports/tf_maildir.h	Sat Feb 26 22:51:42 2011 +0100
++++ b/src/transports/tf_maildir.h	Sun Feb 27 21:51:22 2011 +0100
 @@ -16,7 +16,7 @@
                  uschar *);
  extern int    maildir_ensure_sizefile(uschar *,