You have various choices it seems...
 

• Install, play with it then remove. See what gives.
• Restore with backup afterwards if necessary (I use Acronis). I always recommend a backup strategy before installing any new software regardless.
• Uninstall old copies of Sonar afterwards and reinstall.
• Use another PC or dual boot to a fresh operating system.
• Buy and install the full version of Sonar X3 afterwards.

 
NB During the demo installation I would point the VST file path to somewhere else.
 
Sadly virtualization probably won't be an option.
If you are looking for guarantees you probably won't find any here, the rest is up to you (sorry). BTW what operating system are you running right now? (Will it meet the requirements?)
 
Cheers...

I'm on Windows 7, I have a backup strategy, etc etc. I have pointed out at least twice above that merely taking backups isn't going to suffice. What I want to know is quite specific, and should be answerable by someone on the Cakewalk team, if not by anybody else here. It's not unknowable information. In fact you'd expect someone would have explicitly tested scenarios like this before they shipped a free trial. (But since I work in software, I know that what should be done and what does get done are often different.)

While waiting for the Cakewalk staff to visit the thread, there is a method to directly contact them here

> In fact you'd expect someone would have explicitly tested scenarios like this before they shipped a free trial.

Not at all really, all software including demos software may or may not introduce oddities. I doubt Cakewalk can absolutely guarantee the demo will 100% cleanly remove itself although there is a good chance business will be as usual afterwards (I'm sure it's designed for that). The only safe way is to backup and restore or use another PC or dual boot as others including myself have said (yes I do understand it is not an option for you, sorry about that). Working in software you know that often dependencies get updated and occasionally DLL's float around afterwards (often does no harm, usually DLL's to do with third parties away from Cakewalk). You also know that all scenarios are not tested.
  
Thanks..

FWIW, I always make a backup copy of all the \shared folders before installing a new version, as well as any sub-folders under \users'appdata\cakewalk that aren't unique - basically anything the doesn't have a version number suffix.   And I've never had an issue going back if and when needed.    Anecdotal, yes, but it sure seems to work.
 

CakeAlexS
 I doubt Cakewalk can absolutely guarantee the demo will 100% cleanly remove itself

Of course they can. They have a precise list of the components that get installed and uninstalled. They can also easily test this situation. Install 8.5, install trial, uninstall trial, test 8.5. The only issue is whether they care enough to do it, and have the resources to do so.
 
And can we please stop saying "make backups"? I have regular backups, but that is not the issue. Individual files can be easily restored but resetting registry settings and the like after a month of testing is impractical. Similarly trying to selectively restore shared files is a hassle, especially if it involves a reinstallation.

Kylotan
Of course they can. They have a precise list of the components that get installed and uninstalled. They can also easily test this situation. Install 8.5, install trial, uninstall trial, test 8.5. The only issue is whether they care enough to do it, and have the resources to do so.

Exactly. With unlimited resources, of course anything is achievable, but please understand that actually they can't test this in all scenarios, there could be many different scenarios you are running a PC after all. Being in software you know this I'm sure :) Perhaps you should test it yourself (that is after all what a demo is for).
 
Really the whole point of demos is for you to try and eval it, if it doesn't work for you don't use it, if you are expecting some sort of quality of service with install/uninstall, well good luck with that... Hopefully it will work, otherwise you will need to find another way of doing this (I can't think what else, it's already been stated by many people on this thread, and no options are acceptable to you... fair enough). Otherwise I would expect the same sort of thing to happen after uninstall as with any Windows app.
 
Anyway I hope Cake comes back with the response you are expecting but I wouldn't hold your breath to be absolutely honest with you.
 
> And can we please stop saying "make backups"
 
I think I wrote earlier maybe you missed this.... "yes I do understand it is not an option for you, sorry about that".
So I say again, sorry about that... Your only other real option is another PC or dual boot, or take a chance and see what happens.

Kylotan
Hi all, I'm going to give the X3 trial a go, to see if it's worth upgrading from 8.5. However, if I do not choose to upgrade, I'll have to uninstall X3 at the end. So I have 2 questions:
 
1) Will installing X3 alongside 8.5 cause any problems? I assume they will use the same VST paths along with various other shared files, so hopefully the installation doesn't overwrite anything that 8.5 relies upon?
2) Similarly, if I uninstall X3, it will be removing files from shared locations - has anybody verified that uninstalling X3 won't remove any plugins that were installed for earlier versions of Sonar?

Regarding (2), I haven't uninstalled Sonar in any incarnation that I can recall, but doesn't it ask if you want to remove the shared components? If so, you can just say "no."

All versions of SONAR including the trial install common files to the shared utilities folder and some common plugins as well. The common files are:
- VstScan.exe which is the vst scanner
- PluginManager.exe
- Several plugins 
 
So yes this indeed will modify the 8.5 installation. While all these updates contain new code they are all designed to be backwards compatible so no harm should come of installing it. If you choose to uninstall the demo later these shared components will be left behind so technically you would have updates for those modules.
 
If you are paranoid about wanting to go back exactly to 8.5 I would suggest additionally manually backing up the shared utilities and vst folders should you decide so that you can fully roll back if necessary.

When I first installed the 64-bit version of Sonar 7 on a new Windows 7 platform I had a problem with Plugin Manager. Someone (Bitflipper) suggested that installing a trial copy of Sonar X2 might solve the problem. I tried this and it worked. It fixed the problem and there were no adverse effects.

I can't say whether the same would apply to 8.5 and X3 though.