MPLAB X keeps track of various settings in its persistence data files. If for some reason one of these files become corrupted, deleting them will restore MPLAB X to its default state and new persistence files will automatically be created.
Persistence files may be found in the following directories depending on your platform:
- Windows XP:
C:\Documents and Settings\username\Application Data\.mplab_ide\dev\version
- Windows Vista, Windows 7 and later:
C:\Users\username\AppData\Roaming\.mplab_ide\dev\version (before v3.00)
C:\Users\username\AppData\Roaming\mplab_ide\dev\version (v3.00 and later)
- Mac OSX:
To "reset" MPLAB X to its default state, simply delete all the files inside the version directory (where version is something like "1.80"). However, if for some reason you want to go back to the "troubled" state, just save the contents of the version directory somewhere else. Putting them back into version later will restore the settings that were saved in those files.
You can always find the user directory path described above by selecting Help > About from the main menu.