I just completed a new DAW build and am currently installing SONAR Platinum, associated extras and 3rd-party plugins. See my signature line below for the specs of the new DAW. I'm currently working on stand-alone versions of synths and synths in instrument tracks. MIDI input isn't working for any of these most of the time but it sometimes does. Right now, it's not working at all.
 
I have a AKAI MPK49. It shows up reliably in Device Manager (DM) under Sound, video and game controllers and when I remove/insert the USB connector into the back of the MPK49, it's line in DM goes away and comes back. I've uninstalled and reinstalled it in DM and I've tried to update drivers. According to DM I have the latest drivers and the device is working properly.
 
I've tried several google searches finding nothing useful except a video that stated that there are only 10 MIDI ports available in Windows 10. That could be the problem because when I started SONAR once in this process, a dialog box indicating that there were no MIDI ports available for the (3) MPK49 MIDI inputs. That doesn't happen now. All 3 MPK49 MIDI inputs are listed in the stand alone versions of the synths and in the MIDI Device list for SONAR.
 
In the video the instructor used a KORG app to display all connected MIDI devices and select the active ones. I don't think I have and haven't found such an app. Can someone help me troubleshoot and correct this problem? 
 
Thanks.

You might be experience a Windows MIDI port problem due to hidden "ghost" ports.
Here's a good article Craig Anderton wrote several years ago that might help correct your issues.
 
http://www.harmonycentral.com/articles/solving-the-windows-midi-port-problem.
 
Moving forward, always try to use the same USB ports for all your devices when unplugging and plugging them back in ~ might help eliminate the "ghost MIDI port" issue in the future, if that is indeed what the current problem is.
 
Also, MIDI-Ox is a GREAT freeware MIDI port monitoring and routing utility for Windows - 
Highly recommended, works great under Windows 10.
 
http://www.midiox.com/
 

riversw88, thanks. I read Craig's article and created the batch file and followed Craig's instructions. The Akai MPK49 is shown as one of the active (not grayed out) Sound, video and game controllers. I also found and deleted 5 grayed out Microsoft Streaming devices and the Microsoft Trusted Audio Drivers and tried the keyboard again with a stand alone synth (AAS GS-2) but still no luck. The Audio Setup for GS-2 shows all three of the MPK49's MIDI inputs selected. I can play the GS-2 by clicking notes on the GS-2's displayed keyboard. There must be something else and I'm feeling pretty stupid at this point since I must be overlooking something.
 
I also fired up MIDI-OX. It show the three MPK49 MIDI inputs but  I couldn't figure out what to do with MIDI-OX.
 
Thanks again.
Bill

The best thing to use MIDI-OX for is the MIDI monitor.  It shows exactly what data that you are sending from the controller.  No guessing required! 
 
1. It's the best way to troubleshoot MIDI connectivity issues.  If your keyboard, cables, or ports are messed up, you should be able to spot that quickly.
 
2. Otherwise, if that part is good and you are getting what you need into the computer reliably, then you can focus on setting up the ports in your other software.

abacab
The best thing to use MIDI-OX for is the MIDI monitor.  It shows exactly what data that you are sending from the controller.  No guessing required! 
 
1. It's the best way to troubleshoot MIDI connectivity issues.  If your keyboard, cables, or ports are messed up, you should be able to spot that quickly.
 
2. Otherwise, if that part is good and you are getting what you need into the computer reliably, then you can focus on setting up the ports in your other software.

Ok. It works. When I press a a key [C4 for example] MIDI-OX displays the on and off messages. I'd been using another program [Vyzex MPK49] which is tailored to managing MPK49 presets for that function. I think the MPK49 is working and Windows is receiving inputs from it. Vyzex and MIDI-OX see the inputs but SONAR and the standalone synths don't.

OK, can you launch the standalone Cakewalk Rapture Session?
 
Look at the top menu item "MIDI", and select your MPK49 input.  See if you can play any notes in this synth, and if the virtual keyboard on Rapture Session reflects your key presses.

On a lark I moved the MPK49 USB 2.0 connection to the spare USB 2.0 port on the DAW back panel. Now it works. I viewed hidden devices in Device Manager and there was a grayed out MPK49 which I uninstalled and a new one for the new port. Also all the grayed out ports that I'd previously uninstalled were back. When I tried the keyboard in SONAR and stand-alone synths it worked. I don't know why but it did. So I switched it back to the original USB 2.0 port. It still works and all the grayed out connections are gone. Looks like Windows Device Manager is seeing ghost, but they are gone for now. I don't know what the problem is, but it seems to be something in Windows 10. Here's a screenshot I took earlier showing the grayed out ports that are now gone. https://www.dropbox.com/s/d18mqks9o58xsr9/Hidden%20Sound%20Devices%20170621.png?dl=0
 
 Here's a screenshot showing that there are no longer any ghost Sound, video and game controllers which I'm guessing is the normal situation. https://www.dropbox.com/s...7PEWQjwBkkBSkmNma?dl=0

abacab
OK, can you launch the standalone Cakewalk Rapture Session?
 
Look at the top menu item "MIDI", and select your MPK49 input.  See if you can play any notes in this synth, and if the virtual keyboard on Rapture Session reflects your key presses.

abacab, thanks. See my previous post. Looks like my MPK49 input problem is solved for now. My MPK49 now works with all the standalone synths that I've installed so far including Rapture Session and with SONAR. I've got a separate problem with Rapture and Rapture Sessions that I'm going to address in a new post.

Glad you got it sorted!  The mysteries of Windows 10, LOL!!!

abacab
Glad you got it sorted!  The mysteries of Windows 10, LOL!!!

Well the ghost ports and problem is back today. In fact I don't think the ghost ports ever disappeared. I think that I forgot to select "Show hidden devices" the next time I opened Device Manager.
 
Today all I did to get the MPK49 working was remove and re-insert the the USB 2.0 plug from the port. I've never had to do that before.
 
At point I'm thinking that this is a Windows 10 problem and has nothing to do with SONAR are the synths I'm using. So I'm going to jump to the Microsoft Community for some help. However, I'm not optimistic. I looked there before I posted this problem here and noticed that most MIDI related questions received only one or two basically uninformed responses and were left unanswered.