If passwords have been inserted as plain text, then you must set the SaltKey for that record to negative 1 ( -1 ). From there you must touch the web.config file, perform an iisreset, or any other action that forces the application to restart. When the application restarts, the startup logic will salt/hash any password that has a SaltKey of -1 and reset the salt key to the correct value. Any customers that have a plain text password that will not be able to log in until you've followed those instructions
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