Thanks Stacho 5.4.1+d281f25 (2017-12-29) has resolved this (discarding of log file contents) for the projects that it was affecting. Those projects still raise the "warning -- error deleting temporary directory" but at least now I have a valid log file. Will perhaps help me to track down what is going on with some projects and not others. If you have any insight as to why this problem is so selective, I would be interested to know. Bruce From: Therion [mailto:therion-bounces@speleo.sk] On Behalf Of Bruce Mutton via Therion Sent: Sunday, 24 December 2017 9:34 AM To: 'List for Therion users' <therion@speleo.sk> Cc: Bruce Mutton <bruce@tomo.co.nz> Subject: [Therion] Therion compiles but overwrites log file Back in September I mentioned similar problem to what I am experiencing now, with one project. An error deleting temporary log files causes the log file contents to be deleted and replaced with this message. On this occasion, Therion seems to be compiling just fine, but I have no (meaningful) log file! "C:\Program Files (x86)\Therion\therion.exe: warning -- error deleting temporary directory -- C:\Users\Bruce\AppData\Local\Temp\th7916" The temporary folder contains a single file like data.1 attached. This is only an occasional problem. Mostly I get a valid log file, but it does seem to be persistent with some projects and not others. What I would like is for the above message to be appended to the log file, and not replace the contents of the log file. Therion 5.4.1+e7e9d34 (2017-12-14) Bruce