I have a new PC,
 
ASUS Z9PE-D16C/2L servers Mainboard,
Intel Xeon E5 CPU*2,
128G memory
500G SSD*2
 
USB DEVICES:
SONAR VS-700
SL-MKII
 
when I use SONAR X3, I usually can't find my vs-700 or SL-MKII in MIDI DEVICES of SONAR ，But this time I can find Vs-700 AND SL-MKII in Device Manager of WIN7 64bit，
Some times, change USB port, SONAR can find, but other times it was useless.
 
WHY？
 
sorry for my chinese english !
 

This article might explain your problem. Windows only allows a certain number of MIDI ports. The problem is that it "remembers" previous MIDI port assignments and thinks they're real. If you delete these "ghost" MIDI ports you will avoid exceeding the Windows limit on MIDI ports.

Also, check your USB ports.  You will have some USB3 ports mixed in with USB2's.  The 700 might not work on the USB3's.

Did you download any drivers that the VS700 may need. I do not remember if its a plug and play or if you need drivers installed first.
 
Also, i notice you have 128iggs of ram. WOW!!!! I didnt even relaizre you could have that much ram. Is that a typo?
 
CJ

CJaysMusic
Did you download any drivers that the VS700 may need. I do not remember if its a plug and play or if you need drivers installed first.
 
Also, i notice you have 128iggs of ram. WOW!!!! I didnt even relaizre you could have that much ram. Is that a typo?
 
CJ

It's not plug-and-play, good point. You definitely need to download the drivers as well as the control panel app from the Roland site.

[lang="en"]Thanks, I will try the next
[lang="en"]But the problem is that in my I7 computer, never had this problem, too WIN7 system，the same equipment

[lang="en"]THANKS
[lang="en"]USB3 ports will have problems, but I really connected to the USB2 port on the

[lang="en"]Drive is surely right, previously were normal on the old I7 computers.
[lang="en"]Really 128G, because I'm in 'Hollywood String(Brass)', according to need a lot of memory

maomao
[lang="en"]Thanks, I will try the next
[lang="en"]But the problem is that in my I7 computer, never had this problem, too WIN7 system，the same equipment

That doesn't matter. You can be using the same system for years but once you add just one more MIDI port than the Windows limit, it won't be recognized. Please follow the directions in the article I mentioned in Post #2 to see if that helps.

Did you install the drivers BEFORE connecting the VS-700 to your PC's USB port?