Dear all, I wonder there are somebody who occasionally encounter data import problem in Relion (2.0 or 2.1b). Sometimes I have such a problem with the following errors when I try motioncor or ctf estimation after importing data. ERROR: Cannot read file It does not exist File: /home/bumhan/repo_relion2.1b_fix/relion/src/image.h line: 163(or sometimes 147) In this case, the data was negative stain data, which are converted from tif to mrc using EMAN2-e2proc2d.py. (same error occurs regardless of data type; even mrc micrograph from cryo-EM and mrcs particle stack file from EMAN hdf) Sometimes when I change the data directory name to other, the imported data can be processed in next step(ctf estimation). Sometimes when I edit the directory path to absolute path in the micrographs.star of Import directory, it works. These happened only once per each. Mostly, when I freshly restart importing and ctf estimation, it did not work, showing the errors above. I have no idea how to fix this problem. And it is also weird that sometimes job_pipeline.star file is not generated in Import directory. Is this because I installed Relion inappropriately? In the installation, there was no error but some warning (related to GUI-main-windows). Thank you, Han Bum Han Ryu Ph.D student (Combined) Structural Biology LAB., Dept. of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, South Korea