System Integrity Protection (SIP) on OSX Sierra (10.12) prevents change of file mod #1
Description
The simple fix provided in the apple script does not work with System Integrity Protection (SIP) enabled on OSX 10.12 because /var is not writable even with administrative privileges.
A temporary but undesirable workaround is to disable SIP (has to be done in single user mode). I do not recommend disabling SIP. If you still encounter the dreadful device is busy message - unplug and re-plug device respectively reboot your machine. They should temporary solve your problem.