Hi, When I read the Affymetrix HGU133 spike-in data using spikein<-ReadAffy() I get no problems. From a different directory, with rgu34a CEL files, after trying chip<-ReadAffy(), I get the message Error in validityMethod(object) : No slot of name "phenoLabels" for this object of class "phenoData" I never used to get this message. I have installed the developers versions of the software but I still get the problem. What is going wrong? Best wishes and thanks in advance, Harry -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~ Dr Andrew Harrison Tel: 44 (0) 207 679 3890 Biomolecular Structure and Modelling Unit Fax: 44 (0) 207 679 7193 Biochemistry and Molecular Biology Dept. University College London Gower Street Email: harry@biochem.ucl.ac.uk London, WC1E 6BT, UK http://www.biochem.ucl.ac.uk/~harry ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~