The piano roll stopped opening one day. I'm not aware of any changes that I may have made to cause the issue. I've used Sonar over 10 years and feel pretty darned versed with it normally, just can't seem to solve this issue.
 
Here's what I've tried so far:

• Made sure all Sonar updates are current (up to March 2017 update, which ironically improves the piano roll)
• If I double-click the midi track, nothing happens.
• ALT-3, nothing happens.
• Nothing is opening in the multidock. I've tested expanding the dock, as well as opening other items that DO appear in the dock to make sure that the piano roll isn't hidden there somehow.
• I reset the screensets, no luck.
• Uninstalled & reinstalled Sonar completely, no luck.
• Moved all the .ini files from my user profile's SONAR Platinum folder and allowed Sonar to recreate, still no luck.
• I disabled all but one of my computer's monitors to make sure that the piano roll wasn't somehow off-screen, all the other windows reset but piano roll didn't come back.
• I submitted a support request to Sonar, hoping to hear back soon.
• Using the track view, I can switch to the NOTES view and in-line editing works, but with very inefficient workflow.

 
It feels like SOMETHING still needs to be reset. Perhaps buried config files or registry settings. Has anyone run into this before?
 
Edit: This is Sonar Platinum running on Windows 10

I've had this happen - try this tip from computer geek:
The easiest way to get back a hidden window is to just right-click on the Taskbar and select one of the window arrangement settings, like “Cascade windows” or “Show windows stacked.”

Get Hidden Windows Back with a Keyboard Trick
There’s also a simple keyboard trick you can use if you don’t want to rearrange all your windows. First make sure you’ve got the off-screen window selected as the active window. You can do this by pressing Alt+Tab until that window is active or clicking the associated taskbar button.

After you’ve got the window active, Shift+right-click the taskbar button (because just right-clicking will open the app’s jumplist instead) and choose the “Move” command from the context menu.

At this point, note that your cursor changes to a “Move” cursor. Now, you can use your arrow keys to move the window. You should also just be able to tap any of the arrow keys and then move your mouse slightly to have the window pop back onto the screen.

Hey beegee! Thanks for the reply, really appreciate it. I just tried your recommendations, but unfortunately no dice. It seems that Windows doesn't see the individual Sonar windows (console, piano roll, track view, etc) as separate from the single Sonar app Window. It seems to be within Sonar itself that the PRV window is stuck. I'll keep plugging away, and again truly thank you for the reply!

these is a little arrow to collapse the multi dock. Perhaps this was pressed by accident ?
Im surprised that changing screensets has reset the MD to its default state.
 
Have you tried right clicking on a midi track= Choose Views/Piano roll view ?
 
When the multi dock is open, click on the dock tab and make sure "Lock contents" is not checked.
 
That should keep you busy for a bit

chuckebaby
these is a little arrow to collapse the multi dock. Perhaps this was pressed by accident ?
Im surprised that changing screensets has reset the MD to its default state.
 
Have you tried right clicking on a midi track= Choose Views/Piano roll view ?
 
When the multi dock is open, click on the dock tab and make sure "Lock contents" is not checked.
 
That should keep you busy for a bit

Hey chukebaby- thanks for jumping in! I did make sure that the multidock isn't collapsed. I can expand it up and use the staff/event/sequencer views, just not the piano roll. I just tried right-clicking the clip itself and going to View/Piano Roll, but still no dice.
 
The "lock contents" thing is interesting. The piano roll doesn't show up as a tab in the multi-dock at all, so I don't have that option for piano roll. It does show up for other views in the multidock. I played with it a little, but doesn't seem to bring my by piano roll.
 
I feel like I'm takin crazy pills here! This is the weirdest thing!
 
Thank you so much for your suggestions, really do appreciate it!

 
hmmm,
Have you tried a brand new project as well ? (not a custom project template).
Still no dice hu ? Let me brain storm for a bit and i'll get back to you.
 
The only thing I can think of besides that is if you are accidentally clicking on a track that is not a midi track (just double check).
Sorry im not doubting you just trying to problem solve, you know what I mean.
 
Is it possible also: that you minimized the PRV with your mouse by accident ?
Try hovering over the bottom of the track view and when you see a double arrow, click and drag up.
The shortcut to show/hide the MD/PRV is: "D" and SHIFT + D with minimize/maximize the MD.

chuckebaby
 
hmmm,
Have you tried a brand new project as well ? (not a custom project template).
Still no dice hu ? Let me brain storm for a bit and i'll get back to you.
 
The only thing I can think of besides that is if you are accidentally clicking on a track that is not a midi track (just double check).
Sorry im not doubting you just trying to problem solve, you know what I mean.
 
Is it possible also: that you minimized the PRV with your mouse by accident ?
Try hovering over the bottom of the track view and when you see a double arrow, click and drag up.
The shortcut to show/hide the MD/PRV is: "D" and SHIFT + D with minimize/maximize the MD.

No apologies, I totally appreciate the troubleshooting help. D / Shift+D do open the multidock, but it will only show the staff/event/sequencer views, no luck on the piano roll. Thank you though!
 
I have a ticket in with Sonar support, does anyone have experience with them? Do they usually get back with you quickly?

Every time I have encountered this it was due to a change of monitor number/configuration switching between systems. IIRC on one occasion I had to manually change an x/y window placement value in either an ini file or registry value. I just can't recall where! 

Well - I have this figured out. Sort of. There's definitely a bug allowing this to happen, but I figured out a way to deal with it until Cakewalk sorts out their end. This is super confusing, I'll try my best to explain.
 
Before the below process, I completely uninstalled Sonar (again), even cleared out the c:\ProgramData\Cakewalk files, User ROAMING files, and then the normal c:\Program Files (64/86)\Cakewalk files. From a files and file-stored settings perspective, my system was CLEAN. Reinstalled, issue persisted, and settings weren't actually all gone.
 
Let's call the starting state of Sonar BROKEN. This is the state where the Piano Roll View (PRV) will not open, as described above.
 
Separate from the HKLM Cakewalk registry keys, there is a user registry key: HKCU\Software\Cakewalk Music Software\Sonar\Platinum which stores a ton of Sonar settings for your individual Windows user. I renamed this key then relaunched Sonar. It went back through all of its First-Time-Setup stuff. Then I created a new project, and finally the PRV worked! (let's call this Sonar state GOOD). I saved this new project file (let's call this file CLEAN), thinking that the registry must have just gotten corrupt, and the problem was solved.
 
This is when the real fun starts. I then opened one of my old project files (let's call these files TAINTED), and it sent Sonar back to the BROKEN state! My new saved CLEAN project file's PRV wouldn't even load. If I create a new project, PRV won't load. However! If I close out of Sonar completely, opened my new CLEAN file FIRST, the PRV works. If I closed out of Sonar and opened one of my TAINTED files, is sends Sonar back to BROKEN.
 
This means a few things:

1. When Sonar is first opened, opening my new CLEAN file will fix the BROKEN state of Sonar.
2. The TAINTED project files seem to be permanently tainted. They 100% consistently send Sonar to BROKEN.
3. When Sonar was BROKEN initially, I wasn't able to create a truly CLEAN file until I reset the Windows user registry settings completely. Using this new registry key set, I can create new CLEAN files. Reverting to my OLD registry key set, I wasn't able to create a CLEAN file no matter what I did.
4. When Sonar is GOOD, I can create new projects that all work correctly. However reopening a TAINTED project sends Sonar to BROKEN, and I have to close out and reopen a CLEAN project again.

 
In summary, if anyone runs into this problem, here's my advice:

1. Close out of Sonar completely.
2. Rename the registry key above (don't delete).
   1. **Note - I needed to do this step in order to get a clean project file. It's possible that you may be able to open old CLEAN projects (that existed before your corruption point) and use these to get Sonar back to GOOD. If not, you may need to do this registry change to generate your clean file.
3. Go through the first-run config process, create a new project file, verify PRV is working, then save the project as something like "Fix Sonar" and keep it. From my experience, you should be good moving forward if you're only working on files created since the registry reset.
4. If you still have to work with old TAINTED files
   1. Keep in mind that opening these files will send Sonar to BROKEN.
   2. Open the tainted file, you dare-devil you.
   3. You probably want to bounce all of your tracks (effects off) and save them somewhere, then either write down all your plugin settings or save track templates.
   4. Close Sonar completely
   5. Re-open, and open your "Fix Sonar" project. This will put Sonar back into the GOOD state.
   6. Create a new project to replace your tainted project. Confirm PRV opens.
   7. Import your old tracks, recreate plugin settings, or import your track templates and your bounced waves.

 
What I haven't gotten to try yet is to open these CLEAN and TAINTED files in a new Windows user profile, and also another computer completely. This might completely change things, but from the consistent effects of opening the clean/tainted files, I expect the same results.
 
Also as a general note to Cakewalk, I put in a support ticket a couple of days ago and I haven't heard anything at all. I attempted the Call Me Back support option, but it's effectively disabled on the website saying support is busy. I also tried calling the Boston HQ but no one answered. I don't know what the typical support turnaround time is, but this is extremely disappointing. I'm fortunate that I work another job as my primary income, but if I were only producing music for a living, I would have been completely dead in the water unable to work. When this issue started, I was running Platinum already but my support had lapsed. I paid $200 to renew the support specifically to get help with this issue (which looks to be an actual software bug not a user issue), and didn't hear anything from the support team. I lost hours and hours in my limited schedule that I could use for production work. If I were running Sonar in a commercial studio, ran into this issue and couldn't get help immediately, I would likely lose clients and income. I've bought each version of Sonar since Producer 3. Sonar is amazing as a DAW, and I really want to see it considered alongside Pro Tools as an industry standard. With this type of support, however, it's not yet realistic. Cakewalk - I'd be happy to speak further about this.
 
Community - you guys rock! I wasn't aware of the forum until I was researching this issue, but I plan to be a busy community member moving forward. I genuinely appreciate your tips and suggestions and I'm pumped to return the favor!

Given the symptoms recurring upon opening an older project after a complete reset that solved the issue it is still not beyond the realm of possibility that the PRV is opening off screen, and that window position persists with subsequent projects. Are you absolutely certain that is not the case? How many monitors are connected to your system, and have you saved the older project with more monitors than you are currently using?
 
I am certainly not saying that it the PRV is not 'broken' as you say, but it is certainly worth making sure you have done everything possible rule out the offscreen window option given that the symptoms still all fit. 
Welcome to the forum, and good luck with this!