The Warsaw Uprising triggered massive reprisals by the Germans and led to the destruction of most of the city.

The Home Army and its leadership was loyal to Polish Government in exile (based in London) and not enthusiastic about becoming a part of Soviet empire. The plan/hope was that the Home Army would capture Warsaw and claim the restoration of Polish government which would be quickly acknowledged by Western powers.

It was further expected that RedArmy would keep advancing quickly but would prefer cooperation with the-now-reestablished government rather than a direct confrontation/hostile take over.

There were also other, potentially worse, scenarios/risks to consider

A. unorganized/anarchic uprising in Warsaw would be a disaster

B. without some kind of active action from Home army, German armies might have established a strong defense of the city resulting in massive street fighting later on

both of these could potentially be worse than an organized uprising

Source: "The Secret army" by Bor-Komorovski