Hi Erba,
Honestly, I have ANDERSON acceleration on because I inherited a file with these keywords written in when I was taught how to use CRYSTAL for frequency calculations - and worked pretty well so far with our other systems so I thought to leave it alone (though it was more for pharmacuetical systems). Thanks for the suggestion, I'll try it out if with the original TOLINTEG 10 10 10 10 20 and see what happens.

Thanks,
Peter