Solution To: Maya 2016 Outliner Window Not Showing Up

PROBLEM: Maya Outliner Window Is Missing.

SOLUTION: Refer Maya Troubleshooting Guide.

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Issue:

In some instances, Maya will not start or strange issues inside the UI will occur like missing menus or slow performance in the UI when moving objects in vertex mode, due to corrupted preferences.

Solution:

Refresh the preferences by using the following steps: 

Mac:

1. In the Finder, click the Go menu and then click "Go to folder..."
2. Type /Users/USERNAME/Library/Preferences/Autodesk/maya/VERSION/
3. Click "Go"
4. Find the prefs folder and rename it to prefsOld
5. Restart Maya and if prompted to select the option to create default preferences.

Windows:

1. Rename the prefs folder found in the following location to something like prefsOld:
   • Windows 64-bit: C:\Users\USERNAME\My Documents\maya\VERSION\
   • Windows 32-bit: C:\Users\USERNAME\My Documents\maya\VERSION\
2. Restart Maya.
3. If prompted to, choose the option to Create Default Preferences.

Linux:

1. Rename the prefs folder found in the following location to something like prefsOld: 
   • ~<username>/maya/VERSION/
2. Restart Maya.
3. If prompted to, choose the option to Create Default Preferences.

Note: On all systems it is possible to rename the folder that is named the version of maya for instance "Documents/maya/2016" can be renamed "Documents/maya/2016Old" to reset more files.

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Source:https://knowledge.autodesk.com/support/maya/troubleshooting/caas/sfdcarticles/sfdcarticles/Reset-Maya-to-Default.html
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