Hi Matt, I have the same requirements, did you find a solution ?

Thank you

This is still a problem in v10. Has anyone found a reasonable workaround for this issue?

Looking at this myself rn having upgraded a v7 site to v10 recently and spotted the same issue.

Just knocked up an interceptor to prefix the email address with an underscore which circumvents the duplicate email validation:

angular.module("umbraco.services").config(["$httpProvider", function ($httpProvider) {
    $httpProvider.interceptors.push(function ($q) {
        return {
            'request': function (request) {
                if (request.url.startsWith('/umbraco/backoffice/umbracoapi/member/PostSave')) {
                    request.data.value.email = '_' + request.data.value.email;
                }
                return request || $q.when(request);
            }
        };
    });
}]);

The underscore then gets trimmed off in a member saving notification handler:

using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Notifications;

public class MemberSavingNotificationHandler : INotificationHandler<MemberSavingNotification>
{
    private readonly HttpContext httpContext;

    public MemberSavingNotificationHandler(IHttpContextAccessor httpContextAccessor)
        => this.httpContext = httpContextAccessor.GetRequiredHttpContext();

    public void Handle(MemberSavingNotification notification)
    {
        if (this.httpContext?.Request.Path.ToString() is not string url || !url.StartsWith("/umbraco", StringComparison.OrdinalIgnoreCase))
        {
            return;
        }

        foreach (var member in notification.SavedEntities)
        {
            member.Email = member.Email.TrimStart("_");
        }
    }
}

You'll need to be careful if you are checking if the email is dirty as now it always will be; you'd need to load the old version and compare old email vs new.

Not tested this thoroughly yet or stopped to ponder side effects so use at your own risk!

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