the solution for my ur22 mk2 because its class compliant.
i had problems with the yamaha steinberg usb driver as well. very short loud clicks, every 30 seconds, in every recoring, at any setting, with any yamaha/steinberg driver an different daw´s and even some dropouts.
at first use the newest firmware. that was helpfull for most of my dropout problems.
if you don´t need the playback/ loopbackfunction or what it´s called, (i dont know whats about this dsp stuff, if you need the usb driver for this function), you don´t need the yamaha steinberg usb driver at all. a least for the ur22 mkII
since i uninstalled the yamaha/steinberg driver, (after spending lots and lost and lots… of time and nerves and testing out every driver and everything and a helpless steiberg-support) and since i run my interface with the native apple audio core driver, wich is part of the osx and don´t needed to be installed at all, i had no problems anymore.
the only thing i had to change, i did a manually correction of the latency-correction in my daws for a perfect result. unfortunally there is no way to do so in garageband. but the sync is good enough anyways.a delay of 2ms and a few samples in my case with my ancient 2008 imac.
i know, this post is not new, but maybe it can help somebody struggeling with the usb drivers.
greeting to all
oh yes, to uninstall the yamaha/steinberg driver. you´ll find the uninstaller as a part of it, in the installer of the used yamaha/steinberg usb-driver. start the yamaha/steinberg usb driver installation and there you´ll find the option to uninstall the driver! a restart of your mac is necessary.