diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index 5c806af..0d0c3eb 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -1,48 +1,53 @@
 class GroupsController < ApplicationController
   before_action :authenticate_user!
 
   before_action :group, only: [:show, :create_member, :destroy_member, :search_member]
   before_action :user, only: [:destroy_member]
 
   # GET /groups/1
   def show
     @domains = @group.domains
   end
 
   # POST /groups/1/members/
   def create_member
-    @user = User.find_by_email!(params[:email])
+    @user = User.find_by_email(params[:email])
+    if !@user
+      redirect_to group_path(@group, anchor: 'tab-members'), alert: "User '#{params[:email]}' not found!"
+      return
+    end
+
     membership = @group.memberships.find_or_create_by!(user_id: @user.id)
 
     redirect_to group_path(@group, anchor: 'tab-members'), notice: "#{membership.user.email} is now a member of #{@group.name}"
   end
 
   # DELETE /groups/1/member/1
   def destroy_member
     membership = @group.memberships.find_by!(user_id: user.id)
     membership.destroy!
 
     redirect_to @group, notice: "#{membership.user.email} was successfully removed from #{@group.name}"
   end
 
   def search_member
     results = []
 
     if params[:q].present?
       uids = group.users.pluck(:id)
       results = User
                 .where('email like ?', "#{params[:q]}%")
                 .where.not(id: uids) # Exclude group members
                 .limit(10)
     end
 
     render json: results.map { |r| Hash[:id, r.id, :email, r.email] }
   end
 
   private
 
   def user
     @user ||= User.find(params[:user_id])
   end
 
 end