If you used pyfrc 2015.0.x and uploaded code to your robot there was a critical bug that may prevent your robot from running robot programs (affects python and Java). To fix this, please upgrade pyfrc to the latest version, and run the following command:
Code:
Windows: py -m pyfrc.robotpy.fixbug
Linux/OSX: python3 -m pyfrc.robotpy.fixbug
Additionally, if you upgrade pyfrc, any future code deploys will check for this bug and repair it if found.
If you want to fix this manually, you can ssh in as admin, and execute
Code:
rm /var/local/natinst/log/FRC_UserProgram.log
We apologize for any inconvenience. More information can be found at
https://github.com/robotpy/pyfrc/issues/14.
Successful teams - in almost any aspect of life (i.e. not just robotics) - don't make excuses and assign blame when something goes wrong. They improvise. They adapt. They overcome. They correct the problem and move on. - dlavery [more] 
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