Dear Arefeh, Arp/warp works with standard space groups, therefore you have to reindex P21221 to P21212. In this message from Anastassis Perrakis you can find some advice: https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0709&L=CCP4BB&T=0&F=&S=&P=100954
Michele Arefeh Seyedarabi wrote: > Hi, > > I have a question; recently I have encountered a few space groups which are > not supported by Refmac5. Examples include I2 and P21221. Both these space > groups have been identified as the best solutions for the two different > datasets I am working on using Pointless. However, I am faced with > difficulties in Refmac5, and the program fails to complete when I select > refinement cycles with Arp-waters...with the message saying 'space group not > supported'. > > Any suggestions on how this problem could be overcome? > > Regards, > > Arefeh >