Windows 7 GTX 770
Broken: 2.76b f337fea
//Short description of error/Exact steps for others to reproduce the error
In the addons panel, I unchecked copy attributes and saved settings, subsequently when starting Blender it's enabled whenever I press ctrl+c but it's still unchecked in preferences. It disables if I check+uncheck it but re-enables after starting Blender again.
Note: I enabled it by default several versions ago (2.6x I believe) and while I just install over previous versions, I recently uninstalled prior to installation.
I found that just removing/deleting the addon fixes this but it installs with Blender by default, recreating the problem.//
The blenrig addon activates copy attributes addon & calls several operators, this can cause issues with startup/save user settings with both already activated, this is now a known issue & on @Juan Pablo Bouza (jpbouza) to do list.