diff --git a/checkin_notes b/checkin_notes
index 3f20ecbe1f..a09f6d17d2 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -8776,3 +8776,12 @@ Charlie 2 Dec 2011
         Installer.cpp
         PostInstall.cpp
         release_boinc.sh
+
+Charlie 2 Dec 2011
+    - Mac installer: for files in projects and slots directories, if the 
+        executable-by-owner permission is set, ensure that the 
+        executable-by-group bit is also set.
+        
+    clientgui/
+        mac/
+            SetupSecurity.cpp
diff --git a/clientgui/mac/SetupSecurity.cpp b/clientgui/mac/SetupSecurity.cpp
index f2d2f71c0e..350faaaebd 100644
--- a/clientgui/mac/SetupSecurity.cpp
+++ b/clientgui/mac/SetupSecurity.cpp
@@ -691,6 +691,12 @@ static OSStatus UpdateNestedDirectories(char * basepath) {
             retval = UpdateNestedDirectories(fullpath);
             if (retval)
                 break;
+        } else {
+            // Since we are changing ownership from boinc_project to boinc_master, 
+            // make sure executable-by-group bit is set if executable-by-owner is set 
+            if ((sbuf.st_mode & 0110) == 0100) {    // If executable by owner but not by group
+                retval = DoPrivilegedExec(chmodPath, "g+x", fullpath, NULL, NULL, NULL);
+            }
         }
             
     }       // End while (true)