Running multiple instances of Charles
If you need to run multiple instances of Charles on a single Windows machine, such as in a Citrix environment, you need to make a few changes to how you use Charles.
In the Charles folder in Program Files, edit the Charles.ini file and remove the "single.instance=dde" line, then save the Charles.ini file.
Each user will need to configure Charles to use a different port. I suggest setting Charles to use a dynamic port.
If you need to run multiple instances of Charles as the same user you need to use a command-line option to direct Charles to use a different config file.