Went to open Sonar 8.5, X3, and Platinum and got this error message:does not run on windows or there are errors in .dll  reinstall program. It give you a list of the .dll s. I did a clean reinstall of Platinum it open and every look fine then I close and try reopen and got the same error message. Windows 10 is pass the ten days so no restore point. Has anyone had this problem and a solution? Jay

Can you post the actual DLL error ?
Is it CJ Library.DLL ? or "Bad image error" ?
The more info the better.
 
And how did you reinstall ? did you do a full reinstall or just reinstall sonar ?
https://www.cakewalk.com/Support/Knowledge-Base/2007013392/SONAR-2015-Clean-Install-Instructions
 
Also, I would make sure you have Windows up to date and possibly look for a windows update that may have caused the error.
However I personally think it could be an Anti Virus issue myself (reputation scan removing DLL files and Sonar repopulating erroneous ones).

I did a full clean install. I just put Platinum on this laptop it open but would not reopen.In X3 CjLibrary.dll-TTSlibsndfile.dll, Sonar 8.5 TTSlame.dll-Platinum- CWVideoengine.dll-TTSLame.dll I am using Avast Safe zone for Anti-Virus which I'm replacing. I just try to open X3 got a error.

anything in windows event log?

Hi. I agree with Chuck. I believe this is a AV issue. Try disabling it before installing SONAR.
Follow the instructions in the link above before re installing.
All the best.

A lot of these DLL's are safe but anti viruses flags them because of Reputation scans (they are not known files)
I could be wrong but I think this is what the problem is. Try setting up an exclusion for all cakewalk directory's including Program files/cakewalk, exc. 
 
I would ditch the Safe zone as soon as possible. you don't want a virtual desktop running while your using a digital audio work station. If this is the issue please reply back so others may reap from the benefits of this issue as it has come up in the past few weeks a few times.
http://forum.cakewalk.com/Sonar-not-designed-to-run-on-windows-m3660589.aspx#3661024
im curious if its safe zone causing the problem.
 
Also make sure you are running the installer as Administrator and don't forget to Reboot your PC.
Don't put reboot off as it needs it to finish installing components.

I check to see if I had the Latest win10 update. I had 1604. Now updated to 1703 and everything is find. Look in your settings, systems and about page Windows10 said I had the latest update 1604, That's wrong check the web.