Dear Bruce In the project file I sent with my previous email, the E0 of the standard Fe foil spectrum was set to 7128.5 eV, and the E0 of the foil spectra associated with the sample spectra were set to 7112 eV. If I set the E0 value of the standard Fe foil spectrum to 7112 eV as well, the "auto-align" function works properly again. Playing around a little bit further, it appears that the auto align function finds the correct solution as long as the difference between the E0 values assigned to the standard foil and the foil spectrum to be aligned is less than or equal to 5 eV. However, I wonder why the choice of E0 should affect the alignment function? Best regards, Andreas °°° °°° °°° °°° °°° °°° °°° °°° °°° °°° Andreas Voegelin, PhD Eawag - Swiss Federal Institute of Aquatic Science and Technology Ueberlandstrasse 133, CH-8600 Duebendorf, Switzerland Tel: +41 58 765 54 70 mailto:andreas.voegelin@eawag.ch http://www.eawag.ch/~voegelan