very poor fit and auto reference?

[Geoffrey Payne]

Hello Everyone. I'm wondering if anyone has thoughts about why the QuickFit in one  brain spectrum (3T) is very good, and in a repeat visit is very poor (see figure attached; left column). The data quality looks similar in both cases. If I try the AdvancedFit I get a similarly poor fit, unless I deactivate the autoreference on the preprocessing tab, after which the fit is much improved (right column), although there is still quite a lot of baseline noise around the peaks which is not visible in the original spectrum. Any thoughts very welcome. Thanks.  Geoff