diff --git a/checkin_notes b/checkin_notes
index 4aaf1ea2a5..a0a1440155 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -7117,3 +7117,10 @@ David  21 Aug 2009
         sched_customize.cpp,h
         sched_send.cpp
         sched_version.cpp
+
+Charlie 21 Aug 2009
+    - Mac client: in procinfo_setup(), use rss keyword not rsz in ps command 
+        for compatibility with OS 10.6 while keeping OS 10.3.9 compatibility.
+
+    lib/
+        procinfo_mac.cpp
diff --git a/lib/procinfo_mac.cpp b/lib/procinfo_mac.cpp
index f8a864e257..6ae41ced23 100644
--- a/lib/procinfo_mac.cpp
+++ b/lib/procinfo_mac.cpp
@@ -62,7 +62,6 @@ int procinfo_setup(vector<PROCINFO>& pi) {
 // ppid       parent process ID
 // poip       pageouts in progress
 // rss        resident set size in Kbytes
-// rsz        resident set size + (text size / text use count)
 // time       accumulated cpu time, user + system
 // vsz        virtual size in Kbytes
 //
@@ -84,7 +83,7 @@ int procinfo_setup(vector<PROCINFO>& pi) {
 // root; this was perceived by some users as a security risk.
 
 
-    fd = popen("ps -axcopid,ppid,rsz,vsz,pagein,time,command", "r");
+    fd = popen("ps -axcopid,ppid,rss,vsz,pagein,time,command", "r");
     if (!fd) return 0;
 
     // Skip over the header line