If you get :

[Oh My Zsh] Would you like to check for updates?
Type Y to update oh-my-zsh: Y
Upgrading Oh My Zsh
Cannot pull with rebase: You have unstaged changes.
Please commit or stash them.
There was an error updating. Try again later?

To solve this on OSX or Server Without proper permissions or no root privileges:

#1)
 cd ~/.oh-my-zsh/
#2)
 git add .
#3)
 git commit -m "commit message"
#4)
 upgrade_oh_my_zsh