I recently upgraded to Mojave from Mountain Lion on a Mac Mini Late 2011. After upgrade, the Mail app would not connect to the mail server any more. I followed a few online articles and dragged the
/User/Library/Containers/com.mail.app/ folder to the desktop and restarted but it would not connect. So, I deleted the mailbox and tried to install it again, but, no luck.
Finally, I created a new user account in the OS and successfully set up the mail accounts there. However, I don't want to migrate the whole account over since there are many settings, scripts, and network connections for that user in apps such as Adobe suite, etc.
Is there any other steps I can take to fix the mail app within the initial user instead of trying to migrate the user? Is deleting the mail app and then reinstalling Mojave from the startup going likely to fix the issue or is there any other plist files or directories I can remove to allow macOS to regenerate that would be causing errors in one user account but not the other? I saw that some file structure within the
com.mail.app were different than a fresh Mojave install.