Accessing the FlowJo error log on Mac OS X (And potentially for any other Application)

Problem: Something is broken or isn't working correctly in FlowJo, but doesn't produce any error messages or debug friendly output.

I was recently trying to debug why a FlowJo plugin I was developing wasn't working. Unfortunately, FlowJo seems to swallow all of the errors that occur in the background, without reporting them to the user.

FlowJo 10.4 on Mac OSX doesn't appear to support the Open Log Window command shown here.

Here's a trick that will allow you to get much more detailed debugging information on FlowJo to help you work out what's going on.

Solution: Run the FlowJo app directly from the command line to capture outputted log messages

Open the terminal and run the following:

/Applications/FlowJo.app/Contents/MacOS/flowjoJavaApplicationStub

You'll see that by launching the FlowJo app directly from the command line, you'll get log output (including errors!) on the command line:

Expanding to other applications

You should theoretically be able to use the same approach (cd inside the .app folder, into whatever-app.app/Contents/MacOS/ and run the application in that folder directly.