Cyclone III fitting forever

Hi all,

I use Quartus II version 10.1cb for my design in Cyclone III LS with "security separations" features, It worked fine.

I upgraded to Quartus II version 10.1sp, the fitting ran for 3 days without complete.

When I converted all security regions to unsecurity regions, it finished in one hour.

Can anyone tell me what wrong with this.

Thanks.