I downloaded Windows 10 on July 28. I have had nothing but problems . Between 2 and 12 duplicates of many photos. Any duplicate deleted will delete all copies and leave a non removable and non available photo entry. Also renaming or renumbering a photo will make it no longer available. Does not effect photos after August. I had about 70,000 photos with windows XP. When I went to Windows 7 pro, it reloaded to 107,000. At least I could delete the duplicates with no problem. When Windows 10 installed, I ended up with 307,000 photos. Today I have over 310,000 photos. Totally unmanageable. I do not recommend Windows 10 until they address this problem. I contacted customer service 8/12/2015 and was told it caused by a virus and after the virus was removed it would be resolved. Not happening! Be very careful. I have lost a lot of photos already. Any change to Collections, Pictures, or Photo Gallery is also done to the others. I will try to resolve this again but will probably return to Windows 7 pro next week.
It seems unlikely that Win10 will duplicate your photos - they are just user files of no interest to Win10.
Please explain how these "duplicates" appear on your machine - How are the duplicate files named? Do the duplicates appear in the same or different folder than the pre-existing file?
Are you running the latest version of Essentials, ie. "Windows Essentials 2012"?
I have just resolved a so-called duplicate photos problems on another user's Win10 system, and it seem as though it is User Error. He appears to have been importing the photos in a manner which created duplicates - he is a little foggy on his procedure so could not confirm precisely what he has been doing, but I suspect his duplicates have been there from well before Win10 came along. We deleted duplicates (via Photo Gallery) and nothing untoward happened to the other copy(s) of the same file (which in his case had the identical file name, but in a different folder.)