diff --git a/app/controllers/moderator/bulk_reverts_controller.rb b/app/controllers/moderator/bulk_reverts_controller.rb
index 3d708f5a9..87e956504 100644
--- a/app/controllers/moderator/bulk_reverts_controller.rb
+++ b/app/controllers/moderator/bulk_reverts_controller.rb
@@ -1,24 +1,35 @@
 module Moderator
   class BulkRevertsController < ApplicationController
     before_filter :moderator_only
+    before_filter :init_constraints
     helper PostVersionsHelper
+    rescue_from BulkRevert::ConstraintTooGeneralError, :with => :tag_constraint_too_general
 
     def new
-      @constraints = params[:constraints] || {}
     end
 
     def create
-      @constraints = params[:constraints] || {}
       @bulk_revert = BulkRevert.new(@constraints)
 
       if params[:commit] == "Test"
         @bulk_revert.preview
         render action: "new"
       else
-        @bulk_revert.process!
+        BulkRevert.delay(:queue => "default").process(@constraints)
         flash[:notice] = "Reverts queued"
         redirect_to new_bulk_revert_path
       end
     end
+
+  private
+
+    def init_constraints
+      @constraints = params[:constraints] || {}
+    end
+
+    def tag_constraint_too_general
+      flash[:notice] = "Your tag constraints are too general; try adding min and max version ids"
+      render action: "new"
+    end
   end
 end
diff --git a/app/logical/bulk_revert.rb b/app/logical/bulk_revert.rb
index 148569b09..191d446d4 100644
--- a/app/logical/bulk_revert.rb
+++ b/app/logical/bulk_revert.rb
@@ -1,6 +1,17 @@
 class BulkRevert
+  BIG_QUERY_LIMIT = 5_000
   attr_reader :constraints
 
+  class ConstraintTooGeneralError < Exception ; end
+
+  def self.process(constraints)
+    obj = BulkRevert.new(constraints)
+
+    obj.find_post_versions.order("updated_at, id").each do |version|
+      version.undo!
+    end
+  end
+
   def initialize(constraints)
     @constraints = constraints
   end
@@ -18,14 +29,19 @@ class BulkRevert
 
     if constraints[:user_id]
       q = q.where("post_versions.updater_id = ?", constraints[:user_id])
+    end
 
-      if constraints[:added_tags] || constraints[:removed_tags]
-        hash = CityHash.hash64("#{constraints[:added_tags]} #{constraints{removed_tags}}").to_s(36)
-        sub_ids = Cache.get("br/fpv/#{hash}", 300) do
-          sub_ids = GoogleBigQuery::PostVersion.new.find(constraints[:user_id], constraints[:added_tags], constraints[:removed_tags])
-        end
-        q = q.where("post_versions.id in (?)", sub_ids)
+    if constraints[:added_tags] || constraints[:removed_tags]
+      hash = CityHash.hash64("#{constraints[:added_tags]} #{constraints{removed_tags}} #{constraints[:min_version_id]} #{constraints[:max_version_id]}").to_s(36)
+      sub_ids = Cache.get("br/fpv/#{hash}", 300) do
+        GoogleBigQuery::PostVersion.new.find(constraints[:user_id], constraints[:added_tags], constraints[:removed_tags], constraints[:min_version_id], constraints[:max_version_id], BIG_QUERY_LIMIT)
       end
+
+      if sub_ids.size >= BIG_QUERY_LIMIT
+        raise ConstraintTooGeneralError.new
+      end
+
+      q = q.where("post_versions.id in (?)", sub_ids)
     end
 
     if constraints[:min_version_id].present?
diff --git a/app/logical/google_big_query/post_version.rb b/app/logical/google_big_query/post_version.rb
index be0424f55..9351a20ef 100644
--- a/app/logical/google_big_query/post_version.rb
+++ b/app/logical/google_big_query/post_version.rb
@@ -3,34 +3,50 @@ module GoogleBigQuery
     def find_removed(tag, limit = 1_000)
       tag = escape(tag)
       limit = limit.to_i
-      query("select id, post_id, updated_at, updater_id, updater_ip_addr, tags, added_tags, removed_tags, parent_id, rating, source from [#{data_set}.post_versions] where regexp_match(removed_tags, \"(?:^| )#{tag}(?:$| )\") order by updated_at desc limit #{limit}")
+      query("select id, post_id, updated_at, updater_id, updater_ip_addr, tags, added_tags, removed_tags, parent_id, rating, source from [#{data_set}.post_versions] where #{remove_tag_condition(tag)} order by updated_at desc limit #{limit}")
     end
 
     def find_added(tag, limit = 1_000)
       tag = escape(tag)
       limit = limit.to_i
-      query("select id, post_id, updated_at, updater_id, updater_ip_addr, tags, added_tags, removed_tags, parent_id, rating, source from [#{data_set}.post_versions] where regexp_match(added_tags, \"(?:^| )#{tag}(?:$| )\") order by updated_at desc limit #{limit}")
+      query("select id, post_id, updated_at, updater_id, updater_ip_addr, tags, added_tags, removed_tags, parent_id, rating, source from [#{data_set}.post_versions] where #{add_tag_condition(tag)} order by updated_at desc limit #{limit}")
     end
 
-    def find(user_id, added_tags, removed_tags, limit = 1_000)
+    def add_tag_condition(t)
+      es = escape(t)
+      "regexp_match(added_tags, \"(?:^| )#{es}(?:$| )\")"
+    end
+
+    def remove_tag_condition(t)
+      es = escape(t)
+      "regexp_match(removed_tags, \"(?:^| )#{es}(?:$| )\")"
+    end
+
+    def find(user_id, added_tags, removed_tags, min_version_id, max_version_id, limit = 1_000)
       constraints = []
 
       constraints << "updater_id = #{user_id.to_i}"
 
       if added_tags
         added_tags.scan(/\S+/).each do |tag|
-          escaped = escape(tag)
-          constraints << "regexp_match(added_tags, \"(?:^| )#{escaped}(?:$| )\")"
+          constraints << add_tag_condition(tag)
         end
       end
 
       if removed_tags
         removed_tags.scan(/\S+/).each do |tag|
-          escaped = escape(tag)
-          constraints << "not regexp_match(added_tags, \"(?:^| )#{escaped}(?:$| )\")"
+          constraints << remove_tag_condition(tag)
         end
       end
 
+      if min_version_id
+        constraints << "id >= #{min_version_id.to_i}"
+      end
+
+      if max_version_id
+        constraints << "id <= #{max_version_id.to_i}"
+      end
+
       limit = limit.to_i
       sql = "select id from [#{data_set}.post_versions] where " + constraints.join(" and ") + " order by updated_at desc limit #{limit}"
       result = query(sql)
diff --git a/app/views/layouts/default.html.erb b/app/views/layouts/default.html.erb
index fc3ea685a..95fd2c3df 100644
--- a/app/views/layouts/default.html.erb
+++ b/app/views/layouts/default.html.erb
@@ -12,7 +12,7 @@
   <% if CurrentUser.user.blacklisted_tags.present? %>
     <meta name="blacklisted-tags" content="<%= CurrentUser.user.blacklisted_tags.gsub(/(?:\r|\n)+/, ",") %>">
   <% end %>
-  <% if flash[:notice] =~ /error/ %>
+  <% if flash[:notice] =~ /error/i %>
     <meta name="errors" content="true">
   <% end %>
   <meta name="enable-js-navigation" content="<%= CurrentUser.user.enable_post_navigation %>">
diff --git a/app/views/moderator/bulk_reverts/new.html.erb b/app/views/moderator/bulk_reverts/new.html.erb
index af8caf1c6..9caf16328 100644
--- a/app/views/moderator/bulk_reverts/new.html.erb
+++ b/app/views/moderator/bulk_reverts/new.html.erb
@@ -2,9 +2,11 @@
   <div id="a-new">
     <h1>New Bulk Revert</h1>
 
+    <p>You must preview a bulk revert before processing it. Previews may take several minutes to generate.</p>
+
     <%= form_tag(moderator_bulk_revert_path, :class => "simple_form") do %>
       <div class="input">
-        <label>Updater</label>
+        <label>User Name</label>
         <%= text_field :constraints, :user_name, :value => @constraints[:user_name] %>
       </div>
 
@@ -29,7 +31,10 @@
       </div>
 
       <%= submit_tag "Test" %>
-      <%#= submit_tag %>
+
+      <% if params[:commit] == "Test" %>
+        <%#= submit_tag %>
+      <% end %>
     <% end %>
 
     <% if @bulk_revert %>