Once downloaded, compare the SHA-1 or MD5 hash against official Microsoft MSDN databases. If the hash doesn't match a known good value, delete the ISO immediately.
When searching for "Windows 10 1603," it is important to clarify that Microsoft never officially released a version 1603 windows 10 1603 iso download repack
You can download the latest version of Windows 10 (currently 22H2) directly from the Microsoft Software Download page Older Versions: Once downloaded, compare the SHA-1 or MD5 hash
If you're not comfortable downloading a repacked ISO file, consider these alternatives: consider these alternatives: