All of the 10x application data is stored in the appdata folder
%appdata%\10x\
This includes all of the settings, application state and cached data.
When 10x is run for the first time it will populate this folder with the default settings.
To reset 10x back to the default state close 10x, delete or rename the %appdata%\10x folder and restart 10x. This can be useful in tracking down bugs to see if it only happens with your setup.
Note that the parser cache folder can get very large for large projects.
Log files are created in the %appdata%\10x\ folder. If a log file is already being used by another 10x process a new log file will be created. Otherwise it will re-use the existing log file.
See also: