I have been using Comodo Dragon for a couple of months now and since the beginning I have started CD with the following command line parameters:
–user-data-dir=\comodo\dragon\profile --incognito
Note that there are no spaces in the path to the (portable) profile, so now room for error here 
Since updating to version 4.1.1.8, Comodo Dragon crashes on startup when using the –user-data-dir parameter. Without the –user-data-dir parameter, CD works just fine. The –incognito parameter works flawlessly, too.
I get the Whoa! Comodo Dragon has crashed. Restart now? message.
I have tried repairing, reinstalling Dragon, deleting my profile and starting from scratch - all to no avail 