Q: Desktop Wallpaper keeps going back to the standard wallpaper after reboot

Open Terminal (Applications/Utilities/Terminal.app) and paste this command

rm ~/Library/Preferences/com.apple.Desktop.plist

press 'return' on the keyboard.

Log out, log back in again. Change the wallpaper to what you want. Log out, log back in once more to test.

Any improvement?

Glad to have helped!

you sir! made my day, thanks alot

Also this helped for me

If your wallpaper changes back to default (Galaxy) after reboot or after logout it is because

the wallpaper you set was on another drive.

and this drive loads after your settings are loaded.

MAC OS X Lion / Mountain Lion does not save your wallpaper on the native HDD, rather tries to load the wallpaper from the original HDD, i guess only the path to the wallpaper is saved in the OS X settings.

Anyways..

what happens is that when your OS X boots up it does not find the path to your wallpaper since the HDD you've saved your wallpapers in has not mounted yet.

One basic solution for this is to save your wallpapers in the HDD where you've installed the MAC OS X..

but I didnt want to save all my wallpapers in Native Mountain Lion HDD, so i figured out my perfect fix..!!

This is how i fixed..

I found this file in my Lion install drive.. autodiskmount.plist

Library/Preferences/SystemConfiguration/autodiskmount.plist

If you can't find it on your OS X Install Drive then you can make one by typing

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

<plist version="0.9">

<dict>

<key>AutomountDisksWithoutUserLogin</key><true/>

</dict>

</plist>

rename ur txt file to autodiskmount.plist

save this in your MAC OS X HDD

Library/Preferences/SystemConfiguration/autodiskmount.plist

Voila..!!

restart your system..

Now save your wallpapers where ever you want on your computer and i didnt have to worry about the wallpaper changing back to default.

I just got off the phone with Apple Support.

Go to... Library:Preferences , delete 'com.apple.desktop.plist'

Choose your desktop background; reset computer.

What if there is not such file?? Can't find, Library:Preferences , delete 'com.apple.desktop.plist'??

Having this issue on computers running Lion and Mtn Lion.

I have no such file in Library:Preferences either. I'm running Mountain Lion and my desktop keeps reverting to an old image I was using before upgrading from Lion. I keep finding the same answers to this question, but none of them seem to work for me.

Nope. I use wallpapers randomly selected from my iPhoto albums. I have 4 workspaces. Spaces 2, 3 and 4 have the wallpaper correctly applied. The main workspace still reverts back to the default galaxy wallpaper. I would be glad to help out with any diagnostics and troubleshooting info if you want to request it.

BTW, I tried deleting ~/Library/Preferences/com.apple.desktop.plist - no avail

SORRY, I FORGOT TO ADD A STEP TO FIND THE "com.apple.desktop.plist"

~I'm running a base retina Macbook with Mountain Lion.~

I just got off the phone with Apple Support.

~~~On the Finder bar, click 'Go', hold 'alt/option', click Library.~~~

Now navigate to:

Library:Preferences , delete 'com.apple.desktop.plist'

Choose your desktop background; reset computer.

killall -HUP Dock reloads the Dock and wallpaper.

This isn't a solution, but a workaround:

a) Create a file called "killall_dock.sh" in your home directory, with the following contents:

#!/bin/sh

killall -HUP Dock

b) Save it.

c) Turn on execute permissions (run the command in Terminal.app)

chmod +x killall_dock.sh

d) Add the file killall_dock.sh as part of your Login Items from the System Preferences > Users & Groups preference pane.

Updated workaround. I have created an app to restart the Dock. Follow the instructions and download the app from http://saumilsmac.blogspot.in/2012/08/wallpaper-reverts-to-default-galaxy-at.htm l

Thanks, softwater!  That simple command fixed the issue for me as well.

Softwater's solution worked for me the second time I tried it -- thanks!