Hi: 
I have two computers and on my office computer I just had to do a clean reinstall of Sonar Platinum by Cakewalk because it kept on loosing the usb midi connection for my keyboard.  I do not know why it suddenly started dropping the midi keyboard connection.  FYI, Bandlab's Cakwalk version of Sonar also had the same problem.  However, this problem does NOT exist when I use Cubase 9.5, Mixbus, Samplitude or Studio One 4 or any of my standalone vsts; they all work well; it is just Sonar Platinum and Bandlab's Cakewalk that now disconnect the midi keyboard within a minute of startup.  BTW, I have been using Cakewalk's line since 1994/5 and Sonar is my goto DAW, but it is acting up suddenly dropping the midi keyboard connection.
 
So, I am trying to do a clean install to see if this helps.   I did just did a clean install (reinstall) of Cakewalk's Sonar Platinum, but also need to do the same clean install for Bandlab's version which I know borrows some from the older Sonar Platinum's setup.
 
So, how do I do a clean install of Bandlab's version of Cakewalk Sonar? 
Do I just use the Bandlab Assistant and choose uninstall under the Cakewalk by Bandlab drop down menu?
 
I am using Win10 64bit i5 with 32gigs of ram
 
Thanks
Cecelius2

cecelius2
Do I just use the Bandlab Assistant and choose uninstall under the Cakewalk by Bandlab drop down menu?

That's what I was going to suggest.  However, I am thinking this will not solve your issue.

You may have to turn off power management for your USB root hubs. 

Go to device manager and look at the properties for all root hubs under the item "Universal Serial Bus controllers"

Windows by default has the following setting enabled: "Allow the computer to turn this device off to save power under the "Power Management" tab

Before you remove and reinstall the entire program, try deleting the "TTSSeq.ini" file. Then restart Cake.

I agree that re installing the Software is unlikely the solution to the issue. 
One thing that can work is if your controller came with a USB midi driver, re install that. Often windows 10 updates overwrite factory drivers with generic. 

I find it curious that only Cakewalk and Sonar are dropping the MIDI connection, while the other host apps do not.
 
If it was a MIDI driver issue, or a USB hub power issue, I would expect it to affect all MIDI hosts, and not just Cakewalk.
 
I would focus on the .ini files that could be in common with these two apps.  Then perhaps an uninstall and reinstall couldn't hurt.

Thanks for all this help.  I am going to implement your suggestions and report back.
 
FYI-  I too was intrigued by the fact that Cubase, Studio One, Samplitude, Mixbus and all other midi software work fine, but Sonar/Cakewalk does not.  I am a fanboy of Sonar, so I am not complaining; I am just trying to figure out a solution.
 
Your posts here are helping me diagnose/fix the problem.
 
Thanks again
C2

While I doubt it is necessary, a re-clean install of CbB is similar to http://www.cakewalk.com/Support/Knowledge-Base/2007013392/SONAR-2015-Clean-Install-Instructions
 
The changes are:

• in step 1, uninstall using BandLab Assistant
• in step 5, the registry keys to delete are

• HKEY_CURRENT_USER\Software\Cakewalk Music Software\Cakewalk\Core
• HKEY_LOCAL_MACHINE\Software\Cakewalk Music Software\Cakewalk\Core

• in step 8, the folder to delete is "Cakewalk Core"
• in step 9, delete the contents of folder C:\Program Files\Cakewalk\Cakewalk Core
• in step 10, reinstall using BandLab Assistant

John I agree that it is odd but this topic comes up from time to time as well as people having issues with Audio drivers that work just fine with other DAW's but only Cakewalk being a an issue. I seem to remember the explanation was how Cakewalk is different in it's Windows integration or something like that. It has deeper roots into the OS and there is where these issues might pop up. Sonar likes to see good quality drivers. 

I agree Johnny, but just for grins I would attempt the clean re-install of Sonar and CbB, due to those deep Windows roots.
 
Good drivers never hurts either.  The OP never mentioned what his hardware specs were, such as a MIDI keyboard using a 5-pin DIN MIDI port on an interface, or a MIDI over USB with vendor drivers, or a class compliant USB MIDI interface.  You know, the details...

Update on my progress.  It is now working.  Hurray!
 
I did implement all the changes suggested in this thread but I did them all at the same time; so  I am not sure which suggestion did the trick, but it is now working properly.
 
I did perform a total clean install of both Sonar Platinum and Bandlab's Cakewalk version at the same time so that it would be totally clean install.
Again, Sonar Platinum and Bandlab's Cakewalk are both working.  It then updated Bandlab's version as it had a new update last week. 
 
Just because someone asked about the specs on this DAW, here they are:
  [This is just my secondary DAW (on my home office computer); it has minimum audio and midi devices.]   
    Scarlet 2i2 (1st gen using the latest driver) and a
    Nektar LX61 (which uses microsoft usb driver). 
    ASUS H97-Plus MB with 16gb ram and an i5 4690 processor.
 
Again, I thank you all for your needed help.
 
C2