Hi, Whenever I try to make a continuation file for my simulation I can generate a tpr file using tpbconv but I can't cat the ouput files together afterwards. When I run ">gmxcheck -f closed1122_unrest.trr" on the first trr file I get the following: Checking file closed1122_unrest.trr trn version: GMX_trn_file (single precision) Reading frame 0 time 0.000 # Atoms 189376 Reading frame 910 time 4550.000 ------------------------------------------------------- Program gmxcheck, VERSION 3.3 Source code file: trnio.c, line: 66 File input/output error: Can not determine precision of trn file ------------------------------------------------------- I've tried generating the continuation file from an earlier frame but have the same problem always at frame 910. The file is over 2gb but as tpbconv runs without a problem I don't think that's the problem. Any suggestions? Thanks -- Samantha Kaye Structural Bioinformatics and Computational Biochemistry Group University of Oxford