If you have forgotten your eM Client Startup password and cannot get into the program, then you will have to “Delete the eM Client Settings.dat file” as per @Gary post below from the following thread.
https://forum.emclient.com/t/how-to-reset-the-startup-password-on-em-client-7/60427/2
@Gary post below from the above thread link. This works the same in any eM Client version.
“There is a file you can delete, but you will lose most of your settings. You won’t lose any data, nor items like Rules, signatures and templates”.
"Close eM Client, and then delete C:\Users_[username]_\AppData\Roaming\eM Client\settings.dat. You may have to show hidden items in Explorer to do that.
If you have a Mac, then the eM Client Settings.dat file is in the following hidden folder - “Users\yourusername\Library\Application Support\eM Client”
Note:- To access the eM Client hidden folder on a Mac, first click on your desktop and then “hold down the Option Key”. Then “while holding the Option key click Go in the menu” and select Library" etc.