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You need to rebuild the Launch Services Database by entering the following command in Terminal, followed by pressing enter.

Code:
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user
After you do that, relaunch Finder by holding the Option/Alt key down while you right-click the Finder icon on the Dock, then select Relaunch.
 
Thanks to GGJstudios & robbieduncan you for your help. Now duplicates are not. :D
 
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