is it possible to prevent overwriting a S7 DB?

I would like to prevent anyone from downloading over a db inside a 416-2dp processor to prevent the accumulated values from resetting to their initial values as defined in the db. Is this possible? Does anyone know of another way?

Ah. The problem is that you cannot allways make a backup of the actual values, and there is allways the potential disaster that someone "initialises" a datablock and then uses this for an update.

You cannot protect a datablock in the way you describe.
There is a software option for STEP7 to control access to the PLCs, but I think this is not relevant for you. It is aimed at large customers with central control of programming changes.

This problem is on my own list of S7 shortcomings.