I guess it's no big deal really. I just have to remember to check whether it's past midnight, because if it is and I forget to shut down my Acronis scheduled backup, a reboot takes about 10-15 minutes while it backs up my drives. 

Bitbridge isn't still running when this happens, I check for that as well. I've noticed Bitbridge is still running after every Sonar crash so I automatically go in and stop it before reloading Sonar. 

in taskmanager are you looking under process as well or just applications?
let me ask you this,do you have midi devices pluged?
unplug then/leavethem out untill its not in TM anymore.
your looking for bitbridge or sonarpdr.exe
midi actvity will hold sonar hostage untill the process is dead.
best bet is to log off/reboot takes too long.
just log off and resign in to windows.

i dont see it as much as i used to,they must have added some support for it in x2 because in x1 i saw it alot more.

That happens from time to time to me as well, and have happened since v3 or whatever.

The cause and sollution seem to change with versions as well. At some point it was my MIDI controllers that need to be switched off and on, new update and it was my audio interface. Bought new audio interface and problem went away, new Sonar and one of the MIDI controllers had to be witched off and on, new MIDI controller and then all my controlers had to be switched off and on - and so forth.

Currently, I don't know, but for a long time BitBridge was causing it to hang and only a re-boot would fix it. It takes my machine approx 15 seconds to re-boot so it's not really an issue anymore. But since the latest patch I haven't really experienced it at all.

I used to get this a lot with SP8 on Vista but more during a session than launching. Always required a reeboot. I was always told it was to do with the M-audio driver for my Axiom 49.

Then I went to Win 7 and X1... at first when Sonar crashed I could just end in task man and re-launch, but now it's gone back to having to reboot PC again. I just can't kill Sonarpdr.exe no matter what I cancel, switch off or unplug.

I had a nightmare recently where by I could not launch any projects and Sonar just went staright to white screen ('would you like to submit bug...' or a 'dump has been created at'...). I had recently played with with Saffire Pro 40 settings so it could of been mismatch of project settings but I believe it was a vst and probably amplitube 3. Holding shift and loading no plugs and then doing a fresh vst scan fixed everything for every project.

Either way, whenever Sonar does have a tantrum, I'm back to rebooting again

Thanks
Dean