unity needs to load dfault setup code example
Example 1: unity default layout error
1. Delete LastLayout.dwlt from C:\Users\YOURNAME\AppData\Roaming\Unity\Editor-5.x\Preferences\Layouts\default
2. Delete CurrentLayout.dwlt from C:\Users\YOURNAME\Unity Projects\YOUR_PROJECT\Library
Example 2: unity failed to load window layout
Deleting both the LastLayout.dwlt and the Library/ before attempting to re-open the editor cleared up the issue.