There are quite a few threads about problems with MBox and ASIO. To see the threads search google for
site:forum.cakewalk.com mbox
 
I know of one user who reported success http://forum.cakewalk.com/FindPost/3092320
 
If you do create a new thread; please create it here. Your latency problem is from not running a low latency driver. This is a hardware issue.

The last Mbox 2 Windows driver update was 7 years ago, for an interface that's 12 years old - working in conjunction with a modern system and software. That alone could be the problem.

To be honest, these guys are right. The MBox2 has been known to have its issues in these present times.
Sonar did update its WASAPI support for windows 10 sometime last year, maybe that's an option instead of using the MBox2 driver try WASAPI.

I held on until the bitter end.  So, recommendations for a cheap, efficient, Sonar-friendly, USB interface for one lonely bass player with pretensions of compositional glory?

Also, thanks to all for the quick and helpful replies.  Sorry to jack the thread...

jtorch68
I held on until the bitter end.  So, recommendations for a cheap, efficient, Sonar-friendly, USB interface for one lonely bass player with pretensions of compositional glory?

Also, thanks to all for the quick and helpful replies.  Sorry to jack the thread...

You can get a Focusrite Scarlett Solo for less than a hundred bucks. I wouldn't go cheaper than that. Make sure you get a 2nd Gen model.

I would second the Focusrite Scarlett's. That company updates their drivers frequently and their devices are durable, reliable and Quality.
 
The solos are good but you can get a used 212 for under a 100 bucks.

I bought a Focusrite Solo for my laptop setup, and it's been very stable. Plus you get free/discounted plugins each month. I've got plugins for more than I payed for it last year
Best of luck.

I ordered the Solo.  Delivery by April 2nd.  Thanks for all the help, peeps!

PS - Removing the Mbox2 got rid of both the latency and the timeclock issues.

PPS - I am also gratified to know where to go when trying to figure all this stuff out...