I've been chasing this for a full 8 hours now.
I'm using the Focus Lab Master Config.
All files on the front end - both locally and on my staging server - display perfectly fine.
I can log into CP locally.
I *cannot log into CP on staging. I get the white screen of death.
I turned on debugging. When I access the CP, I get this error:
A Database Error Occurred Error Number: 1054 Unknown column 'session_id' in 'field list' INSERT INTO exp_security_hashes (date, hash, session_id) VALUES (1375809948,'fa2ebb013799a26b30d4acb1964d3156111bb5ff',0) Filename: core/EE_Security.php Line Number: 158
I've attempted as many solutions as I could dig up from Google. Does anything in this particular situation stand out as being the most likely culprit?