diff -urp procmail-3.22.orig/src/mailfold.c procmail-3.22/src/mailfold.c
--- procmail-3.22.orig/src/mailfold.c	Tue Sep 11 04:58:34 2001
+++ procmail-3.22/src/mailfold.c	Wed Jan 18 12:58:44 2006
@@ -30,6 +30,7 @@ static /*const*/char rcsid[]=
 
 int logopened,rawnonl;
 off_t lasttell;
+static int trunced;
 static long lastdump;
 static volatile int mailread;	/* if the mail is completely read in already */
 static struct dyna_array confield;		  /* escapes, concatenations */
@@ -81,6 +82,7 @@ long dump(s,type,source,len)const int s,
  long len;
 { int i;long part;
   lasttell=i= -1;SETerrno(EBADF);
+  trunced=0;
   if(s>=0)
    { if(ft_lock(type)&&(lseek(s,(off_t)0,SEEK_END),fdlock(s)))
 	nlog("Kernel-lock failed\n");
@@ -120,13 +122,18 @@ jin:	while(part&&(i=rwrite(s,source,BLKS
       }
 writefin:
      i=type!=ft_PIPE&&fsync(s)&&errno!=EINVAL;	  /* EINVAL => wasn't a file */
+     if ((i||len)&&lasttell>=0)
+      { int serrno=errno;
+	if(!ftruncate(s,lasttell)) trunced=1;
+	SETerrno(serrno);
+      }
      if(ft_lock(type))
       { int serrno=errno;		       /* save any error information */
 	if(fdunlock())
 	   nlog("Kernel-unlock failed\n");
 	SETerrno(serrno);
       }
-     i=rclose(s)||i;
+     i=rclose(s)||i; /* if this fails, we should truncate, but it's too late */
    }			   /* return an error even if nothing was to be sent */
   return i&&!len?-1:len;
 }
@@ -237,7 +244,7 @@ dumpf:	 { switch(errno)
 #endif
 	      default:writeerr(buf);
 	    }
-	   if(lasttell>=0&&!truncate(boxname,lasttell)&&(logopened||verbose))
+	   if(lasttell>=0&&trunced&&(logopened||verbose))
 	      nlog("Truncated file to former size\n");	    /* undo garbage */
 ret0:	   return 0;
 	 }