diff --git a/.gitignore b/.gitignore
index 9e998e64..d327dbe8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,3 +13,4 @@
 mkmf.log
 *.gem
 .DS_Store
+Gemfile.lock
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
deleted file mode 100644
index ff4cdf63..00000000
--- a/Gemfile.lock
+++ /dev/null
@@ -1,116 +0,0 @@
-PATH
-  remote: .
-  specs:
-    launchdarkly-server-sdk (6.0.0)
-      concurrent-ruby (~> 1.1)
-      http (~> 4.4.1)
-      json (~> 2.3.1)
-      ld-eventsource (~> 2.0)
-      semantic (~> 1.6)
-
-GEM
-  remote: https://rubygems.org/
-  specs:
-    addressable (2.7.0)
-      public_suffix (>= 2.0.2, < 5.0)
-    ansi (1.5.0)
-    ast (2.4.2)
-    aws-eventstream (1.1.0)
-    aws-partitions (1.418.0)
-    aws-sdk-core (3.111.2)
-      aws-eventstream (~> 1, >= 1.0.2)
-      aws-partitions (~> 1, >= 1.239.0)
-      aws-sigv4 (~> 1.1)
-      jmespath (~> 1.0)
-    aws-sdk-dynamodb (1.58.0)
-      aws-sdk-core (~> 3, >= 3.109.0)
-      aws-sigv4 (~> 1.1)
-    aws-sigv4 (1.2.2)
-      aws-eventstream (~> 1, >= 1.0.2)
-    concurrent-ruby (1.1.8)
-    connection_pool (2.2.3)
-    deep_merge (1.2.1)
-    diff-lcs (1.4.4)
-    diplomat (2.4.2)
-      deep_merge (~> 1.0, >= 1.0.1)
-      faraday (>= 0.9, < 1.1.0)
-    domain_name (0.5.20190701)
-      unf (>= 0.0.5, < 1.0.0)
-    faraday (1.0.1)
-      multipart-post (>= 1.2, < 3)
-    ffi (1.14.2)
-    ffi-compiler (1.0.1)
-      ffi (>= 1.0.0)
-      rake
-    http (4.4.1)
-      addressable (~> 2.3)
-      http-cookie (~> 1.0)
-      http-form_data (~> 2.2)
-      http-parser (~> 1.2.0)
-    http-cookie (1.0.3)
-      domain_name (~> 0.5)
-    http-form_data (2.3.0)
-    http-parser (1.2.3)
-      ffi-compiler (>= 1.0, < 2.0)
-    jmespath (1.4.0)
-    json (2.3.1)
-    ld-eventsource (2.0.0)
-      concurrent-ruby (~> 1.0)
-      http (~> 4.4.1)
-    listen (3.4.1)
-      rb-fsevent (~> 0.10, >= 0.10.3)
-      rb-inotify (~> 0.9, >= 0.9.10)
-    multipart-post (2.1.1)
-    oga (2.15)
-      ast
-      ruby-ll (~> 2.1)
-    public_suffix (4.0.6)
-    rake (13.0.3)
-    rb-fsevent (0.10.4)
-    rb-inotify (0.10.1)
-      ffi (~> 1.0)
-    redis (4.2.5)
-    rspec (3.10.0)
-      rspec-core (~> 3.10.0)
-      rspec-expectations (~> 3.10.0)
-      rspec-mocks (~> 3.10.0)
-    rspec-core (3.10.1)
-      rspec-support (~> 3.10.0)
-    rspec-expectations (3.10.1)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.10.0)
-    rspec-mocks (3.10.1)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.10.0)
-    rspec-support (3.10.1)
-    rspec_junit_formatter (0.4.1)
-      rspec-core (>= 2, < 4, != 2.12.0)
-    ruby-ll (2.1.2)
-      ansi
-      ast
-    semantic (1.6.1)
-    timecop (0.9.2)
-    unf (0.1.4)
-      unf_ext
-    unf_ext (0.0.7.7)
-    webrick (1.7.0)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  aws-sdk-dynamodb (~> 1.57)
-  bundler (~> 2.1)
-  connection_pool (~> 2.2.3)
-  diplomat (~> 2.4.2)
-  launchdarkly-server-sdk!
-  listen (~> 3.3)
-  oga (~> 2.2)
-  redis (~> 4.2)
-  rspec (~> 3.10)
-  rspec_junit_formatter (~> 0.4)
-  timecop (~> 0.9)
-  webrick (~> 1.7)
-
-BUNDLED WITH
-   2.2.3
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index cb66e704..88296f02 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -45,7 +45,7 @@ jobs:
           workingDirectory: $(System.DefaultWorkingDirectory)
           script: |
             ruby -v
-            gem install bundler:2.2.7
+            gem install bundler
             bundle install
             mkdir rspec
             bundle exec rspec --format progress --format RspecJunitFormatter -o ./rspec/rspec.xml spec
diff --git a/lib/ldclient-rb/events.rb b/lib/ldclient-rb/events.rb
index c59db7d0..7b77c4db 100644
--- a/lib/ldclient-rb/events.rb
+++ b/lib/ldclient-rb/events.rb
@@ -443,7 +443,7 @@ def make_output_event(event)
         if @inline_users || is_debug
           out[:user] = process_user(event)
         else
-          out[:userKey] = event[:user].nil? ? nil : event[:user][:key]
+          out[:userKey] = event[:user][:key]
         end
         out[:reason] = event[:reason] if !event[:reason].nil?
         out
@@ -451,7 +451,7 @@ def make_output_event(event)
         {
           kind: "identify",
           creationDate: event[:creationDate],
-          key: event[:user].nil? ? nil : event[:user][:key].to_s,
+          key: event[:user][:key].to_s,
           user: process_user(event)
         }
       when "custom"
@@ -464,7 +464,7 @@ def make_output_event(event)
         if @inline_users
           out[:user] = process_user(event)
         else
-          out[:userKey] = event[:user].nil? ? nil : event[:user][:key]
+          out[:userKey] = event[:user][:key]
         end
         out[:metricValue] = event[:metricValue] if event.has_key?(:metricValue)
         out[:contextKind] = event[:contextKind] if event.has_key?(:contextKind)
diff --git a/lib/ldclient-rb/ldclient.rb b/lib/ldclient-rb/ldclient.rb
index 5d803ef3..37d80e9a 100644
--- a/lib/ldclient-rb/ldclient.rb
+++ b/lib/ldclient-rb/ldclient.rb
@@ -401,6 +401,12 @@ def evaluate_internal(key, user, default, event_factory)
         return Evaluator.error_result(EvaluationReason::ERROR_CLIENT_NOT_READY, default)
       end
 
+      unless user
+        @config.logger.error { "[LDClient] Must specify user" }
+        detail = Evaluator.error_result(EvaluationReason::ERROR_USER_NOT_SPECIFIED, default)
+        return detail
+      end
+
       if !initialized?
         if @store.initialized?
           @config.logger.warn { "[LDClient] Client has not finished initializing; using last known values from feature store" }
@@ -421,13 +427,6 @@ def evaluate_internal(key, user, default, event_factory)
         return detail
       end
 
-      unless user
-        @config.logger.error { "[LDClient] Must specify user" }
-        detail = Evaluator.error_result(EvaluationReason::ERROR_USER_NOT_SPECIFIED, default)
-        @event_processor.add_event(event_factory.new_default_event(feature, user, default, detail.reason))
-        return detail
-      end
-
       begin
         res = @evaluator.evaluate(feature, user, event_factory)
         if !res.events.nil?
diff --git a/spec/ldclient_spec.rb b/spec/ldclient_spec.rb
index f7d215e2..cad4c03c 100644
--- a/spec/ldclient_spec.rb
+++ b/spec/ldclient_spec.rb
@@ -145,19 +145,11 @@ def event_processor
       client.variation("key", user, "default")
     end
 
-    it "queues a feature event for an existing feature when user is nil" do
+    it "does not send an event if user is nil" do
       config.feature_store.init({ LaunchDarkly::FEATURES => {} })
       config.feature_store.upsert(LaunchDarkly::FEATURES, feature_with_value)
-      expect(event_processor).to receive(:add_event).with(hash_including(
-        kind: "feature",
-        key: "key",
-        version: 100,
-        user: nil,
-        value: "default",
-        default: "default",
-        trackEvents: true,
-        debugEventsUntilDate: 1000
-      ))
+      expect(event_processor).not_to receive(:add_event)
+      expect(logger).to receive(:error)
       client.variation("key", nil, "default")
     end
 
@@ -313,6 +305,14 @@ def event_processor
       ))
       client.variation_detail("key", user, "default")
     end
+
+    it "does not send an event if user is nil" do
+      config.feature_store.init({ LaunchDarkly::FEATURES => {} })
+      config.feature_store.upsert(LaunchDarkly::FEATURES, feature_with_value)
+      expect(event_processor).not_to receive(:add_event)
+      expect(logger).to receive(:error)
+      client.variation_detail("key", nil, "default")
+    end
   end
 
   describe '#all_flags' do