How to reinstall OS X Server for Mountain Lion or Mavericks from the Mac App Store
Follow these steps if you previously adopted or purchased OS X Server 2.x (for Mountain Lion) or OS X Server 3.x (for Mavericks) from the Mac App Store and you want to download and install it again.
You can redownload OS X Server for Mavericks or Mountain Lion if you meet one of these conditions:
You purchased OS X Server 2.x or 3.x from the Mac App Store.
You purchased a Mac mini or Mac Pro with OS X Server and adopted OS X Server 2.x or 3.x from the Mac App Store.
Verify that OS X Server is in your iTunes purchase history
From the iTunes menu bar, choose Store > View Account and sign in with the Apple ID that was used to adopt or purchase OS X Server. The Account Information page will open.
In the Purchase History section of the page, click See All to open a list of your previous purchases.
Make sure that OS X Server is in the list of purchases. If it's not listed, make sure that you're signed in with the correct Apple ID.
If OS X Server is not in your list of purchases, but you meet the conditions for redownloading it, contact Apple support.
Then download the software again
After verifying that OS X Server is in your purchase history, follow these steps to download it again:
Open the Mac App Store and make sure that you're signed in with the same Apple ID that was used to adopt or purchase OS X Server.
Use these links to go directly to the appropriate Mac App Store page: OS X Server 2.2.5 for Mountain Lion or OS X Server 3.2.2 for Mavericks.
Click the button that shows the price of OS X Server. The button will change to Buy.
Click the Buy button. You'll be asked to enter the Apple ID again. If OS X Server was in your purchase history, you won't be charged again for the software.
You should see a message explaining that OS X Server can be downloaded or updated free of charge. Click the OK button to begin downloading.
After OS X Server has finished downloading and installing, open the Applications folder and make a backup of the Server app. Store the backup in a safe location. If you don't have a backup and need to download OS X Server again, you can repeat the steps in this article.