Hi Mongo,

I upgraded mongo from 2.2 to 2.6 this afternoon and on completing the upgrade the applications failed to connect to mongo as the previous user and password was "not authorised". It appears the user in the admin collection was deleted by the upgrade. I realise thats a bit unlikely but I am looking for an explanation. The user must of been present in the 2.2 install as thats how the connection would of been authorised. Could it be part of taking down the replica set and the secondary becoming prime that caused the anomaly?

We fixed the issue by adding the user back to the admin database but I would really appreciate an explanation and help diagnosing exactly what happened.

Thanks

Phil