How to find/identify identical duplicate files (Windows 10)?

MyRealNameToo

https://forums.moneysavingexpert.com/discussion/comment/82043603#Comment_82043603

Duplicate file finders tend to work in multiple passes…

Pass 1 - Compare the size of all files, any that have a unique size cannot be a duplicate

Pass 2 - Partial hash - hash code the first 10% of each file and compare any that are unique cant be copies

Pass 3 - Full hash - hash code is created on the full contents of the file

Many stop here, if the full hash is the same then its considered identical because the chances of two non-identical files creating the same 256 code is exceptionally small but as its not 0 then others will do a final byte by byte comparison.

Ignoring here things like photo checkers that arent looking for identical items but are apply some fuzzy logic to find nearly identical.

File name, location, meta data like when downloaded dont form part of the hashing process but metadata thats part of the byte stream is included in the hash process so for example if the first video you downloaded had the creators name embedded in the meta data but the person who had posted the second one you downloaded had removed that then hashing would generate different codes and so wouldnt be flagged as a duplicate even if the actual video is identical