Thanks Jarek,

I tried with below sample, still the client freeze while the background task is updating the data.

global

updating procedure DoImportTest(string errstr)
    begin
    longint i;
    record INVc INr;
   
    i = 10000;
    While (i < 20000) begin
        LogText(0,"Step " & i);
        RecordNew(INr);
        INr.Code = i;
        RecordStore(INr,false);
        //MilliSleep(500);
        i = i + 1;
    end;

    return;
end;   

global
updating procedure ImportTest(string s)
begin
String 255 errstr;
time t;

    logtext(0,"scheduling Importtest");
DoImportTest(errstr);
NewPeriodicTask("ImportTest","ImportTest Idle Task","ImportTest","",5,"");
        return;

end;


global
updating procedure OnApplicationStartupComplete()
    BEGIN
    string 255 s;


    inner.OnApplicationStartupComplete;

    logtext(0,"test");
    if (ServerMode or SingleUserMode) then begin
        ImportTest(s);
    end;

    RETURN;
END;