Yep. It won't expire, and you won't lose functionality, so you're safe. You shouldn't even need to use a Microsoft account if you don't want to use one.
Hello, can you upload me ESD or give me link for download ESD for Windows 10 X64 RS1 1607 ; build 14393 ? T hanks in advance
Made an ISO using morrisman's ESD, I installed it in a VM and examined it, along with a full malware scan, rootkit scan, and spyware scan, and it appears to be clean.