Dear Bruce, I realise you may be travelling soon , This is not a very serious bug as I have work rounds. I was demonstrating linear combination fitting in Athena using the gold thiobacteria example this week. I am using 9.25 on a windows 7 computer. I read in all the data from the cynaobacteria project file I mark 5 or 6 standards In the LCF tab I use marked groups, untick the sum weights to 1 option leaving just the all weights between 0 and 1 option selected. I pick a sample spectrum eg 4.73 I select fit all combinations It rolls through them and reports the apparently correct results but an error message is reported: Redundant argument in sprint at C:/... /AppData/Roaming/DemeterPerl/perl/site/lib/Demeter/UI/Athena/LCF.prm line 780, <F> line 122 Clicking any of the answers in the combinatorics tab brings up this error again. If I do a fit of lot of spectra using the same set of standards, I get a similar error message except this time it is line 906 and some of the combined spectra don't plot properly until you refit them as a single spectra in the standards tab I attach a log file but not a project as I assume you can find that on github! Regards Fred J.F.W. Mosselmans Prinicipal Beamline Scientist I18 Diamond Light Source Ltd Diamond House Harwell Campus Didcot OX11 0DE P + 44 1235 778568 M + 44 7785510211 E fred.mosselmans@diamond.ac.uk -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom