Hi, I'm performing homology modelling with Modeller. My template file is a Ca-only file, but this doesn't seem to be a problem. The .ini, .rsr and .sch files are correctly generated and the optimization begins for the first model (.D00000001) but does not succeed. Here is the end of the .log file : TOP_________> 327 234 OPTIMIZE pair2___223E> Array too small. Increase MPAIRS current maximum, current need: 89694 89694 recover____E> ERROR_STATUS >= STOP_ON_ERROR: 1 1 I do search a little bit for the MPAIRS variable but I don't find it. Furthermore I was already successfull in modeling systems larger than the one I'm working now. Thanks for any help. Stephane.