Upgrade question.

So, I had a full version of Parallels 10, and a few minutes ago I upgraded to 11, but I'm only using the trial to see how it operates before I buy. But when my trial ends, will I be able to continue using Parallels 10? I'm only asking this because I have a Windows 8.1 file with all my data, and I'm worried that I will lose this data once the trial runs out.

 

Yes, P10 will work, the correct procedure for downgrading is starting the Virtual Machine, uninstalling Parallels Tools via Add/Remove Programs (you should do this before it expires), shutting down the Virtual Machine, uninstalling Parallels 11, installing Parallels 10, starting the VM, installing Parallels Tools.