Definitely runs only once, but sends out 4 emails each time it runs.
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same effect on _Windows Server_ and _Redmine 1.4.0_

<pre>
D:\redmine\apps\redmine\htdocs>rake redmine:send_reminders days=1 users="3" RAILS_ENV="production" --trace
Please install RDoc 2.4.2+ to generate documentation.
** Invoke redmine:send_reminders (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute redmine:send_reminders
</pre>

-> sends *3x* Mails with same value

Can´t see why. Seems all alright in *mailer.rb*:
<pre>
# Sends reminders to issue assignees
# Available options:
# * :days => how many days in the future to remind about (defaults to 7)
# * :tracker => id of tracker for filtering issues (defaults to all trackers)
# * :project => id or identifier of project to process (defaults to all projects)
# * :users => array of user ids who should be reminded
def self.reminders(options={})
days = options[:days] || 7
project = options[:project] ? Project.find(options[:project]) : nil
tracker = options[:tracker] ? Tracker.find(options[:tracker]) : nil
user_ids = options[:users]

scope = Issue.open.scoped(:conditions => ["#{Issue.table_name}.assigned_to_id IS NOT NULL" +
" AND #{Project.table_name}.status = #{Project::STATUS_ACTIVE}" +
" AND #{Issue.table_name}.due_date = ?", days.day.from_now.to_date]
)
scope = scope.scoped(:conditions => {:assigned_to_id => user_ids}) if user_ids.present?
scope = scope.scoped(:conditions => {:project_id => project.id}) if project
scope = scope.scoped(:conditions => {:tracker_id => tracker.id}) if tracker

issues_by_assignee = scope.all(:include => [:status, :assigned_to, :project, :tracker]).group_by(&:assigned_to)
issues_by_assignee.each do |assignee, issues|
deliver_reminder(assignee, issues, days) if assignee.is_a?(User) && assignee.active?
end
end
</pre>

btw: SMTP Server is in local network (tried _exchange server_ and _hamster_ )
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