I've not researched this, but it strikes me as unlikely that it's caused by unused MIDI ports.
 
More likely it's that a device is opening the port exclusively, making it unavailable to other programs. This would fit pinguinotuerto's report that the problem only occurs when he starts up Podfarm first. 
 
The "no memory" part of the message may be misleading, since the mere presence of a MIDI port allocates very little memory. SONAR may be just raising a generic error message because it can't open the port and has no way of knowing why.

bitflipper
I've not researched this, but it strikes me as unlikely that it's caused by unused MIDI ports.
 
More likely it's that a device is opening the port exclusively, making it unavailable to other programs. This would fit pinguinotuerto's report that the problem only occurs when he starts up Podfarm first. 
 
The "no memory" part of the message may be misleading, since the mere presence of a MIDI port allocates very little memory. SONAR may be just raising a generic error message because it can't open the port and has no way of knowing why.

Agreed, but OP hasn't responded to my question.

pinguinotuerto

bitflipper
I've not researched this, but it strikes me as unlikely that it's caused by unused MIDI ports.
 
More likely it's that a device is opening the port exclusively, making it unavailable to other programs. This would fit pinguinotuerto's report that the problem only occurs when he starts up Podfarm first. 
 
The "no memory" part of the message may be misleading, since the mere presence of a MIDI port allocates very little memory. SONAR may be just raising a generic error message because it can't open the port and has no way of knowing why.

Agreed, but OP hasn't responded to my question.

 
Sorry, not opening anything before sonar.

I've suddenly been having this problem too.

Wondering if you have an onboard sound card, or something that's running in the background that's talking to either Sonar or your interface?

Oh good idea, I'll check to see if realtek is turned off in  the bios.

Add me to this list of folks suddenly experiencing this.  As a bit of background, I have of late been A/B testing my older POD Farm 2.57 Platinum against the CakewalkTH3 to see if I want to upgrade.  Also of note is that when this does occur, Propellerhead Reason 9.1 (which usually absolutely seamlessly handles MIDI) also can't see my Korg padKontrol or Nektar Panorama P1 controllers -- which were really more or less made for Reason.

So I created another thread ( http://forum.cakewalk.com...Platinum-m3503982.aspx ) before I was referred to this one and followed slartabartfast's recommendation of disabling Chrome's ability to take MIDI over and so far, it seems to work OK.  I'm at work right now, but I wanted to add my findings and methodology so as to be helpful if possible.

It seems to me that POD Farm is a part of this at this point based on others reporting so when I get home, I will experiment a bit to see if I can recreate the issue and if so, what exactly I did to do that.

For me it's very easy to reproduce If I launch PodFarm before SONAR, it always happens.

pinguinotuerto
For me it's very easy to reproduce If I launch PodFarm before SONAR, it always happens.

Then it seems like the fix is easy enough -- don't do that!
 
Thinking about it, this has only happened to me since my attempts to A/B POD Farm with TH3 (which must be run inside of SONAR) so I guess this cinches it.  I may set my Chrome browser back the "Let Chrome Decide" because I have never had a problem with this before and I always use Chrome.  Still, it's good to know that's there -- since I didn't know that before.

As mentioned above, I've also had this happen.  Consistently it's when I open SPLAT after using PodFarm 2.5.  If I open Sonar first, no issues.