How to permanently disable local TimeMachine backups?

Question

Hi,
I have disabled the local TimeMachine using:
  sudo tmutil disablelocal
That all works fine but after a reboot, the local backups are back again. For some reason this setting doesn't survives a reboot.
Can nayone give me some advise on how to permanently disable local TimeMachine backups?
Dennis

Answer 1

Here's how I permanently disable TM local snapshots:
1. create  ~/Library/LaunchAgents/com.wfiveash.disable_tmlsnaps.plist containing:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.wfiveash.disable_tmlsnaps</string>
    <key>ProgramArguments</key>
    <array>
        <string>/Users/willf/bin/disable_tmlsnaps.ksh</string>
    </array>
    <key>WatchPaths</key>
    <array>
        <string>/Library/Preferences/com.apple.TimeMachine.plist</string>
    </array>
</dict>
</plist>
2. create a shell script ~/bin/disable_tmlsnaps.ksh:
#!/bin/ksh -p
# This script is supposed to be run via launchd (see
# ~/Library/LaunchAgents/com.wfiveash.disable_tmlsnaps.plist) when launchd
# detects a change to the TimeMachine.plist file.  This script will determine
# if TM local snapshots has been enabled via the MobileBackups property and if
# it has it will run the setuid disable_tmlsnaps binary.
# prevent launchd throttling respawn warning, must wait 10s before this script exits
sleep 10
integer lsnaps=-1
lsnaps=$(defaults read /Library/Preferences/com.apple.TimeMachine.plist MobileBackups)
if [[ $lsnaps -eq 1 ]]
then
    exec "${HOME}/bin/i386/disable_tmlsnaps"
elif [[ $lsnaps -eq -1 ]]
then
    # there was an error running defaults
    exit 1
else
    exit 0
fi
3. Lastly compiled this C program and named it ~/bin/i386/disable_tmlsnaps.  I set the permissions so it was owned by root and setuid:
* To build: gcc -o disable_tmlsnaps disable_tmlsnaps.c
* sudo chown root:wheel disable_tmlsnaps
* sudo chmod u+s disable_tmlsnaps
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
int
main (int argc, char *argv[])
    int rc;
    rc = setuid(0);
    if (rc == 0)
        rc = system("/usr/bin/tmutil disablelocal");
    return rc;
=================================================================
Now when /Library/Preferences/com.apple.TimeMachine.plist is modified (which happens when TM is enabled or disabled) launched will run my disable_tmlsnaps.ksh script which will check to see if it needs to disable TM local snapshots.