While compiling the code, I pressed the cancel build button, but the build did not stop as seen the build bottun still greyed out abd the cancel still activated. And then I tried to exit from/close the Creator and got following error messages.
 
prj.M0071: Unable to cancel an ongoing build for an unknown reason. Contact Customer Support for technical support on this issue.

The application could not cancel an ongoing build, so the cancel request will be ignored. You can try again or wait until the build is complete.
 

I had to kill the Creator from task manager to restart the Creator.

I'm sorry you had that experience Simon. I use the tool every day and certainly have been known to cancel a build. But I have never had it hang on me. Have you seen this more than once? Do other forum members have this happen?

It is really had to debug one-off hangs like this but we do want to know if it happens. Assuming I do not see a deluge of replies from other users who see the same issue, which would indicate a wide-spread issue, I would contact tech support if you have this happen again. It is likely a PC setup issue that needs to be troubleshot with a support engineer.

-- Mark

 There is no problem if program is builder u can reproram or make correction and updation in your code the build it again and it will override the previous build and new ones is saved

 Reprogram your board

 Downed new or latest version of psoc creator