The simple answer to this is yes it can but generally it will only damage areas that are already broken and the most common part is the pointing in a paving. Pressure washing will not break slabs or block paving as they are too strong. The removal of pointing from paving is always something that we warn customers about as this usually is the weakest part in paving.
Do not let this put you off pressure washing your paving as the benefits for doing so out weight the potential damage. Pressure washing reduces the slip risk by remove moss and algae. It will also bring back the colour to your paving. Unless your paving has been poorly laid then any damage should be minimal, and it can be repaired afterwards.
Posted by Andrew Culverhouse