To generate the log file, you will need to open a program on your Mac called "Console". Open your Applications folder, locate the Utilities folder, and then open the program called Console. The screenshot below will show you what to do next. We often request a Console log file to diagnose unclear issues with one of our Mac programs.
Below is a screenshot of the Console from OS X 10.11 and below.
Once you have cleared the Log in Console and prepared it to search for "propresenter", or whichever program you're using, you can try the same task again. Do not close Console or you'll have to go through the above step again. Once you've done that, go back to Console, open the 'File' menu and select 'Save a Copy As...'. Add your name to the beginning of the file name in the 'Save As' box. You will probably also want to select 'Desktop' from the 'Where' menu to make it easy for you to find this file.
Beginning in macOS 10.12 and up there is a change in the way you will need to send us the report. You will follow similar steps to get us the report in the newer Console app. To start you will need to open Console the same way as before, and open the Log List. You will need to select "system.log" and then clear the report. At this point you will need to search for ProPresenter and then repeat the steps in the application to get the log to populate with data in the "propresenter" search. After you have replicated the issue with Console open and the data showing in Console, you will need to share this with us. To do this you will need to select the "Share" option on the toolbar within Console, and share this with the "Mail" option.
Below is a screenshot of the new Console app in macOS High Sierra.