Hi,

I've problem setting my MIDI. Keyboard is plugged in with a USB-MIDI cable. When I tried to highlight the device in Preference under MIDI device, it always un-highlight itself after I clicked ''apply'' or ''ok'' button. I checked the device under Control Panel, and it said the device is working fine and the driver is up to date. I don't know what when wrong. 

Please help, thanks in advance

What do you mean by HIGHLIGHT? Are you trying to select your MIDI inputs/outputs?

highlight - basically checking the box. 

yeah, I tried to do that, but fail to do so. :(

Are you clicking on the 'tick' to the left of the midi device friendly name?

Just highlighting the device by clicking on its name is not enough to select it and the highlight will disappear when you click 'apply'.
 
As long as the device is ticked that is enough to make it active, no need for it to stay highlighted.

yeah, I did tick the boxes, but they became un-ticked each time I click ''apply'' or ''ok''     :(

Ok...that is strange...never had that happen...maybe try reinstalling your MIDI drivers?

Maybe the midi drivers are opened in another application or a VST? Try opening the midi ports in midiox, often times midiox will pop up an error message box if it can't open a selected port.

I just tried again, this time it worked. I didn't particularly do anything. It's just I messed around with Synthesia before I opened Sonar. Just found out I can open two programs at the same time.  I'm such a tech noob XD  

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After I set the preference in Sonar, I tried to record, but there's no playback sound and I don't even see any sounds profile (not sure if that's what it's called) appeared during recording. 

How do you have things set up? Did you create a simple intrument track? What inputs and outputs are you selecting for your track?

If you are just trying to play your keyboard through Sonar you will not get sound...you need to output it through a soft synth...