ImmCanada, Pls come in

I have applied Canada immigration for three years. In this three years I have updated my application file because I added my daughter. My wife was OB/GNY doc in China. Now after I asked immigration office by letter, they told me they are doing background check. Do you have any idea how long it will take? And I am the main applicator. If something happen from my side, will they reject my application? Thanks.