Hello Sjors, I have just figured out that relion_preprocess command, when used during particle extraction, needs ctffind log files in order to populate particles star file with ctf values. I was surprised since I have all values in micrograph star file, defined by --mic_star option. I thought I could safely remove log files since all info is now contained within star files (luckily, I had a backup, and didn't have to redo CTF). Is there some hidden logic behind such behavior? I think it would be handy if relion could grep values from input star file, since user explicitly defines it during particle extraction. Best regards, Grigory -------------------------------------------------------------------------------- Grigory Sharov, Ph.D. Institute of Genetics and Molecular and Cellular Biology Integrated Structural Biology Department (CBI) 1, rue Laurent Fries 67404 Illkirch, France tel. 03 69 48 51 00 e-mail: [log in to unmask]