Hello,
We have started to run multiple research participants at one time using the same experiment file on different computers, and have found that the summary data file is full of errors. There is data in the wrong columns and it seems to be unusable. Has anyone run into this issue before, and is there a solution that doesn't involve making a new script file for each participant so they can all be neatly in one summary data file?

Thank you very much!

You should not try and have data from multiple participants written to the same data or summary data file stored on some network share -- this will inevitably lead to data file corruption. This can and will lead to problems exactly as you described. Instead have each run write a separate <data> and/or <summarydata> file by setting /separatedata = true in the <data> and/or <summarydata> element. You can easily merge those files at a later point: https://www.millisecond.com/support/docs/v5/html/howto/howtocombinedata.htm