Hi, Thanks very much Bruce and Andrew. I tested Andrew's Cheddar files on this linux machine, and therion ran nice and quickly. I then tested my files on my Windows 7 machine at work. Having seen that it would sometimes hang for Bruce for a minute, I was patient and left it after it hung. It hung for 10.5 minutes, but then was OK. The same is true on linux. I wasn't patient enough! Olly has just had a look (thank you Olly!), and in xtherion he changed: set rx {\S*[^\]\s]\s+\[\d+\]} to: set rx {\s\[\d+\]} It now no longer hangs, and runs as well as ever. We're not sure what the regular expression search was for, or whether changing it matters. As far as I can see it doesn't, as the pdf and log files have already been made. Maybe someone with more therion knowledge will know, and if the cahnge is good maybe it can be applied. Thanks, Jenny