Reloading projects fail

Hey, don't think there's a 2017.05 you probably mean 2017.04?
If you're not aware, you can rollback your install in the command center by right clicking on the product -> rollback -> choose the install to revert to. Might be a good way to check that the previous version is working then maybe try updating to 2017.04 again. Not sure what the actual problem is though.
 
Best. 

Well, even a complete empty project won't load properly. The template files open perfectly.

I've tried 2017.01 to 2017.05. Even a complete re-install didn't do the trick. So weird.

This may also be up to a current update of your grafic card that comes with the windows update.
If "save mode" does not load your project than something is really wrong. You can try to update your grafic card or other system components. A mismatch between audio interface and computer audio card?
But first you should try to go back to a system backup - maybe 3 weeks - if you have turned them on in the windows system.

Noel Borthwick [Cakewalk]
By any chance are you using UWP mode with an offline bluetooth MIDI device selected in MIDI preferences?
Does SONAR work ok if there is no project opened?

SONAR does work properly by itself. I can make music, i can edit stuff, midi is working properly (not using UWP btw) and i can use and save template files.
 
I've tried rolling back to 2017.03 (from 2017.04, clean install), 2017.02 and 2017.01. I've also tried a clean SONAR install of the version 2017.03, 2017.04 and 2017.05. 
 
I am using the UR28M (latest drivers and i used it earlier with SONAR), latest component drivers and the HDD to save the files on, is working properly. I've tried other HDD's (2 other data HDD's) as well. I don't use the onboard graphicscard and soundcard (both are disabled).
 
I use (and tested) other DAW's as well (FL Studio, Ableton, Reaper, ReNoise) and they can save and reopen project files just fine on those HDD's. 
 
I've tried "safe mode", but this didn't do the trick either.
 
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It is sooo weird. I started a track, saving it as a template file (so, with vst's and vsti's) and it opens (menu->new->template) perfectly...So (and this is really annoying) there is a workaround. I can start a track and save it as a template for the time being. Pffff...annoying.

karhide
Sounds very strange. Have you tried running Sonar as administrator?

Yes. And compatibility mode (Windows 8) as well...both without succes..

Canopus
You say that you sometimes run a dual display set-up. Could there be a window currently off-screen waiting for input that seemingly makes Sonar freeze? Perhaps somehow being placed there during a different monitor set-up?
 
And also, does this happen regardless what template you use to create your new projects?

Well, i have tried both undocked and docked in both dual screen and single set-ups. That was my first thought as well. But no. The single screen setup is giving me the same problems with everything dock (or undocked, for that matter).
 
Also, the same empty template saved as a normal project file is giving me problems (so, no plugins, no data, no wavs, etc..). When i then (after the failed loading) reopen the same template, everything is working (within that template) as it should. The problem appears when i try to open "a" normal project file and only then. Ow,,i've tried the bundled filetype as well, without succes.
 
And yes, all templates (and then saved to a project file) aren't opening the way they should.

Canopus
Just a shot in the dark – have you tried to simply press Enter once or twice when things lock up? So if there after all is a hidden window somewhere waiting for input, and the dialog contains a default button, things might get solved? Or optionally the Escape button?

Yeah. I also looked inside task manager to see if something else is running "beneath" SONAR. But, no. No luck...My guess is that the mixer is giving me problems. That screen is acting up (docked, undocked, whatever).

THambrecht
Another shot in the dark:
Unplug your audio interface and open the projects (ignore warnings of no audiocard - and don't save the projects!).
Just to see, if it is not up to your audio interface, worng buffer settings in SONAR, USB-Port, cable ...

I can try that ofcourse, but this wouldn't make sense for the properly working templates...

35mm
THambrecht's advice is good. There is a big difference between template files and project files and in your case project files are not loading. I would also unplug any midi controllers and control surfaces you have and even every other external component you have connected (not including screen mouse, keyboard obviously) just to see if that could be the issue. I had a problem with a surface that suddenly kept making Splat crash on load.

Already tried without midi devices. And now, also without any other device attached. Still, no solution.

And you tried without the audio device connected too? It seems it can only be a problem with your system - software or hardware. It's not Sonar as no one else is having this problem - you have reinstalled Sonar? We can rule out an external device now. Does Sonar actually freeze or just seem to remain busy/loading. If the latter, how long have you left it to load for?
 
Problems like this are very frustrating so you have my deepest sympathy. It could possibly be a registry issue, but that may not be easy to find and fix. I suspect the next step might be to do a clean install of Windows.
 
I hope you manage to resolve the issue and get back to creating again ASAP!

OK glad you have got it working. I haven't had any problems like this with templates. I wouldn't have thought that having no channels in a template would be the problem. I would more suspect the undocked console to be an issue but I don't know why it should be unless something is getting hidden which needs focus. Can you not use a screen set/lens for that?
 

OK I just tested here. Made a template from the Basic.cwt where all I did was change the vst browser to list by type. Started a new project from that template, saved it, closed Sonar, launched Sonar and opened that project. It loaded fine although it did give me a prompt to say there was no audio folder and did I want to create it. Can you share your template with me so I can try that here and see if I get the same issue?

35mm
OK, I am testing in Splat 2017.4 - haven't updated to preview yet. I have made a template pretty much how you described - removed channels, undocked console, list vst by type. No problems reopening projects made from this template. However, I have noticed that undocking the console doesn't get saved with the template, neither does listing vst by type. The console appears docked again and the vst list just seems to stay how you last set it in any project. So I don't think they can be a factor in your issue.

Well, over here, they ARE saved in the template. So something strange is happening there as well then. Not very consistent.

35mm
What version of splat are you running? I'm currently updating to 2017.5 preview.

I have the same behavior in versions 2017.01, 2017.02, 2017.03, 2017.04 and 2017.05. Currently running 2017.04 btw (since that should be the "stable" one)

The docking and vst selection are being saved in the template indeed. If i open another template (build into SONAR), the docking and vst selection are back the way they were.