Trying to tie in a login-user/admin- and sheets that are vissible

First things to check
Application.UserName is something that can easly be changed by user or even left blank or typed differently then in your user sheet
so make sure to use Ucase to put all in capitals

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for the first part of your code below is useless for Case "Reagent" & ase "User"

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i don't know how you want the workbook to function exactly but i would protect before closing otherwise we just disable macro's and open the workbook and see everything anyway.
and you can update your code below to do so

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if you do so then below in red is not needed also

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