One quick thought is - are you trying to scale reflections that don't really exist? I.e are you trying to push your resolution a bit too much? Tony. Sent from my iPhone On 6 Apr 2012, at 20:29, "Yuri Pompeu" <[log in to unmask]> wrote: > Hi everyone, > Sorry for the newbie type problems, but I am just starting to use ccp4 for data processing. > Here is my problem. > After I index and integrate my images using iMOSFLM, I end up with the .mtz files that contains, AIUI, unmerged reflections. > Next I should try to merge and scale experimental intensities, using SCALA. > I am getting an error saying: > **** Giving up > Scala: **** Negative Scales **** > task failed. > > Anything obvious I am missing? > thanks a lot.