(Optional) Backup the AIR SDK by copying the entire directory.
In Flash Builder, for example, copy the AIRSDK directory at:
- Windows 7: C:\Program Files (x86)\Adobe\Adobe Flash Builder 4.7\eclipse\plugins\com.adobe.flash.compiler_4.7.0.349722
- Mac OS: /Applications/Adobe Flash Builder 4.7/eclipse/plugins/com.adobe.flash.compiler_4.7.0.349722