I am using POD XT since 2006 as interface for connecting my guitar to computer. Everything has been worked fine under Windows and on Mac until upgrade to OS X 10.11 El Capitan. From time to time there was a message about communication errors with device in driver configuration window. Because there was no "Repair permissions" option in Disk Utility, I have used "/usr/libexec/repair_packages" command in Terminal. Week ago I made clean install of macOS Sierra 10.12.3 and updated to 10.12.4. Communication problem still appears. There is no low-level tools to repair file permissions in macOS Sierra. How can I fight with this errors? I have MacBook Pro 15 mid 2014 with powerful CPU, enough RAM and fast SDD. There is no special software installed. Only Logic Pro X and iWork. Everything is updated to the newest versions.