Version: 5.4 beta (switch to 5.3)
2D and 3D Mode Settings
Build Settings

Preferences

Unity provides a number of preference panels to allow you to customise the behaviour of the editor.

General

Auto Refresh Should the editor update assets automatically as they change?
Load Previous Project on Startup Should the previous project be shown at startup?
Compress Assets On Import Should assets be compressed automatically during import?
OSX Color Picker Mac OSX Only: Should the native OSX color picker be used instead of Unity’s own?
Disable Editor Analytics Can the editor send information back to Unity automatically?
Show Asset Store search hits Should the number of free/paid assets from the store be shown in the Project Browser?
Verify Saving Assets Should Unity verify which assets to save individually on quitting?
Editor Skin Which color scheme should Unity use for the editor? Professional users have the option of dark grey in addition to the default light grey Personal skin.
Enable Alpha Numeric Sorting This option enables a new button in the top right corner of the Hierarchy window, allowing you to switch between Transform sort (which is the default behaviour) and Alphanumeric sort.

External Tools

External Script Editor Which application should Unity use to open script files?
Add .unityproj’s to .sln Should Unity add UnityScript (.unityproj) and Boo (.booproj) projects to the generated solution (.sln) file? Enabled by default for MonoDevelop and disabled by default for Visual Studio.
Editor Attaching Should Unity allow debugging to be controlled from the external script editor?
Image Application Which application should Unity use to open image files?
Revision Control Diff/Merge Which application should Unity use to resolve file differences with the asset server?

Colors

This panel allows you to choose the colors that Unity uses when displaying various user interface elements.

Keys

This panel allows you to set the keystrokes that activate the various commands in Unity.

GI Cache

Maximum Cache Size (Gb) The GI cache folder will be kept below this size whenever possible. A background job will periodically clear out unused files.
Custom Cache Location Allows a custom location for the GI cache. The cache folder will be shared between all projects.
Cache compression This enables a fast real time compression of the GI Cache files to reduce the size of the generated data. If you need to access the raw Enlighten data you should disable Cache Compression and clean the cache.
Clean Cache Use this button to clean the cache.
Cache Size Current Cache size.
Cache Location Current Cache location.

2D

Maximum Sprite Atlas Cache Size (GB)

Cache Server

Use Cache Server Should the cache server be enabled?
IP Address IP address of the cache server, if enabled
2D and 3D Mode Settings
Build Settings