Just to clarify, there are two actions required to disable steam cloud sync.
First, launch tf2.
Go to options
>multiplayer
>advanced
>scroll down to the bottom, and near the bottom you will see "enable steam cloud sync"
>uncheck this option
>click apply/ok.
Second, go to your steam library
>right click team fortress 2
>click properties
>click the "updates" tab
> uncheck enable steam cloud synchronization for Team Fortress 2