diff --git a/checkin_notes b/checkin_notes
index 973338294a..703e71ea1e 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -6631,3 +6631,10 @@ Charlie  10 Feb 2010
     
     mac_installer/
         PostInstall.cpp
+
+Charlie  10 Feb 2010
+    - Mac Installer: Don't perform user and group conflict check on OS 10.3.9 because it 
+        is not needed and produces false positives on that OS.
+    
+    mac_installer/
+        PostInstall.cpp
diff --git a/mac_installer/PostInstall.cpp b/mac_installer/PostInstall.cpp
index e9b839cb6e..b06760e134 100755
--- a/mac_installer/PostInstall.cpp
+++ b/mac_installer/PostInstall.cpp
@@ -607,6 +607,11 @@ void CheckUserAndGroupConflicts()
     char            cmd[256], buf[256];
     int             entryCount;
 
+    // "dscl . -search /Groups PrimaryGroupID xx" returned a different format before OS 10.4
+    if (OSVersion < 0x1040) {
+        return;
+    }
+    
     entryCount = 0;
     grp = getgrnam(boinc_master_group_name);
     if (grp) {