Comment 3 for bug 1819279

The current version of ubuntustudio-controls (1.12.4) does check to make sure that the the path does exist and that it is a file before attempting to open it. The current version can be installed from the backports ppa: https://code.launchpad.net/~ubuntustudio-ppa/+archive/ubuntu/backports

I do not know if this will correct your problem or not, but it is the version we will be fixing any bugs in.