Well, I am also in the same situation and my background check started on 8th March and since then no update. I am not sure what is the criteria for this. I travelled many countries and initially I thought it could be due to that. However, in watsapp group I could see there are applicant who did not travel and studied in Canada and doing job and their application also gone to security check.
ryanira2 and Medmar are correct. There is no timeline defined for security check and I know people in my watsapp group waiting from past 1 year and I believe this is not fair.
