Hi Pavel, I just collected a 2.85 A dataset with space group P212121, MR went well, however, the refinement was not fine: (eg: Rigid body r=48%, it won't go down anymore). I then ran xtriage, it turned out the my data was pseudo-merohedral twinned. The twin fraction is ~0.02. Twin_law=k,h,-l. It there a way to de-twin the data and then do the refinement or just use the twin_law="k,h,-l" at the command line? Is there a way to specify twin_fraction in the paramenter file? Also re-processed data in P41212 or P43212, the ~25% Rsym indicated the data should still be in P222. Thanks, Tongqing Tongqing Zhou, Ph.D. Staff Scientist Structural Biology Section Vaccine Research Center, NIAID/NIH Building 40, Room 4607B 40 Convent Drive, MSC3027 Bethesda, MD 20892 (301) 594-8710 (Tel) (301) 793-0794 (Cell) (301) 480-2658 (Fax) ****************************************************************************** The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives. ******************************************************************