diff --git a/osu.Desktop/Updater/SimpleUpdateManager.cs b/osu.Desktop/Updater/SimpleUpdateManager.cs
index e404ccd2b3..6956eb30b0 100644
--- a/osu.Desktop/Updater/SimpleUpdateManager.cs
+++ b/osu.Desktop/Updater/SimpleUpdateManager.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System.Collections.Generic;
-using System.Linq;
 using System.Threading.Tasks;
 using Newtonsoft.Json;
 using osu.Framework;
@@ -77,10 +76,10 @@ namespace osu.Desktop.Updater
             switch (RuntimeInfo.OS)
             {
                 case RuntimeInfo.Platform.Windows:
-                    bestAsset = release.Assets?.FirstOrDefault(f => f.Name.EndsWith(".exe"));
+                    bestAsset = release.Assets?.Find(f => f.Name.EndsWith(".exe"));
                     break;
                 case RuntimeInfo.Platform.MacOsx:
-                    bestAsset = release.Assets?.FirstOrDefault(f => f.Name.EndsWith(".app.zip"));
+                    bestAsset = release.Assets?.Find(f => f.Name.EndsWith(".app.zip"));
                     break;
             }
 
diff --git a/osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapProcessor.cs b/osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapProcessor.cs
index db80948c94..483ff2d409 100644
--- a/osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapProcessor.cs
+++ b/osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapProcessor.cs
@@ -1,6 +1,7 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using osu.Framework.Graphics;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Objects.Types;
@@ -23,60 +24,70 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
 
             var osuBeatmap = (Beatmap<OsuHitObject>)Beatmap;
 
-            // Reset stacking
-            foreach (var h in osuBeatmap.HitObjects)
-                h.StackHeight = 0;
+            if (osuBeatmap.HitObjects.Count > 0)
+            {
+                // Reset stacking
+                foreach (var h in osuBeatmap.HitObjects)
+                    h.StackHeight = 0;
 
-            if (Beatmap.BeatmapInfo.BeatmapVersion >= 6)
-                applyStacking(osuBeatmap);
-            else
-                applyStackingOld(osuBeatmap);
+                if (Beatmap.BeatmapInfo.BeatmapVersion >= 6)
+                    applyStacking(osuBeatmap, 0, osuBeatmap.HitObjects.Count - 1);
+                else
+                    applyStackingOld(osuBeatmap);
+            }
         }
 
-        private void applyStacking(Beatmap<OsuHitObject> beatmap)
+        private void applyStacking(Beatmap<OsuHitObject> beatmap, int startIndex, int endIndex)
         {
-            // Extend the end index to include objects they are stacked on
-            int extendedEndIndex = beatmap.HitObjects.Count - 1;
-            for (int i = beatmap.HitObjects.Count - 1; i >= 0; i--)
+            if (startIndex > endIndex) throw new ArgumentOutOfRangeException(nameof(startIndex), $"{nameof(startIndex)} cannot be greater than {nameof(endIndex)}.");
+            if (startIndex < 0) throw new ArgumentOutOfRangeException(nameof(startIndex), $"{nameof(startIndex)} cannot be less than 0.");
+            if (endIndex < 0) throw new ArgumentOutOfRangeException(nameof(endIndex), $"{nameof(endIndex)} cannot be less than 0.");
+
+            int extendedEndIndex = endIndex;
+            if (endIndex < beatmap.HitObjects.Count - 1)
             {
-                int stackBaseIndex = i;
-                for (int n = stackBaseIndex + 1; n < beatmap.HitObjects.Count; n++)
+                // Extend the end index to include objects they are stacked on
+                for (int i = endIndex; i >= startIndex; i--)
                 {
-                    OsuHitObject stackBaseObject = beatmap.HitObjects[stackBaseIndex];
-                    if (stackBaseObject is Spinner) break;
-
-                    OsuHitObject objectN = beatmap.HitObjects[n];
-                    if (objectN is Spinner)
-                        continue;
-
-                    double endTime = (stackBaseObject as IHasEndTime)?.EndTime ?? stackBaseObject.StartTime;
-                    double stackThreshold = objectN.TimePreempt * beatmap.BeatmapInfo.StackLeniency;
-
-                    if (objectN.StartTime - endTime > stackThreshold)
-                        //We are no longer within stacking range of the next object.
-                        break;
-
-                    if (Vector2Extensions.Distance(stackBaseObject.Position, objectN.Position) < stack_distance ||
-                        stackBaseObject is Slider && Vector2Extensions.Distance(stackBaseObject.EndPosition, objectN.Position) < stack_distance)
+                    int stackBaseIndex = i;
+                    for (int n = stackBaseIndex + 1; n < beatmap.HitObjects.Count; n++)
                     {
-                        stackBaseIndex = n;
+                        OsuHitObject stackBaseObject = beatmap.HitObjects[stackBaseIndex];
+                        if (stackBaseObject is Spinner) break;
 
-                        // HitObjects after the specified update range haven't been reset yet
-                        objectN.StackHeight = 0;
+                        OsuHitObject objectN = beatmap.HitObjects[n];
+                        if (objectN is Spinner)
+                            continue;
+
+                        double endTime = (stackBaseObject as IHasEndTime)?.EndTime ?? stackBaseObject.StartTime;
+                        double stackThreshold = objectN.TimePreempt * beatmap.BeatmapInfo.StackLeniency;
+
+                        if (objectN.StartTime - endTime > stackThreshold)
+                            //We are no longer within stacking range of the next object.
+                            break;
+
+                        if (Vector2Extensions.Distance(stackBaseObject.Position, objectN.Position) < stack_distance
+                            || stackBaseObject is Slider && Vector2Extensions.Distance(stackBaseObject.EndPosition, objectN.Position) < stack_distance)
+                        {
+                            stackBaseIndex = n;
+
+                            // HitObjects after the specified update range haven't been reset yet
+                            objectN.StackHeight = 0;
+                        }
                     }
-                }
 
-                if (stackBaseIndex > extendedEndIndex)
-                {
-                    extendedEndIndex = stackBaseIndex;
-                    if (extendedEndIndex == beatmap.HitObjects.Count - 1)
-                        break;
+                    if (stackBaseIndex > extendedEndIndex)
+                    {
+                        extendedEndIndex = stackBaseIndex;
+                        if (extendedEndIndex == beatmap.HitObjects.Count - 1)
+                            break;
+                    }
                 }
             }
 
             //Reverse pass for stack calculation.
-            int extendedStartIndex = 0;
-            for (int i = extendedEndIndex; i > 0; i--)
+            int extendedStartIndex = startIndex;
+            for (int i = extendedEndIndex; i > startIndex; i--)
             {
                 int n = i;
                 /* We should check every note which has not yet got a stack.
@@ -155,7 +166,7 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                     /* We have hit the first slider in a possible stack.
                         * From this point on, we ALWAYS stack positive regardless.
                         */
-                    while (--n >= 0)
+                    while (--n >= startIndex)
                     {
                         OsuHitObject objectN = beatmap.HitObjects[n];
                         if (objectN is Spinner) continue;
diff --git a/osu.Game.Rulesets.Osu/Objects/Slider.cs b/osu.Game.Rulesets.Osu/Objects/Slider.cs
index 2af1de7355..44185fb83a 100644
--- a/osu.Game.Rulesets.Osu/Objects/Slider.cs
+++ b/osu.Game.Rulesets.Osu/Objects/Slider.cs
@@ -215,7 +215,7 @@ namespace osu.Game.Rulesets.Osu.Objects
                     var distanceProgress = d / length;
                     var timeProgress = reversed ? 1 - distanceProgress : distanceProgress;
 
-                    var firstSample = Samples.FirstOrDefault(s => s.Name == SampleInfo.HIT_NORMAL)
+                    var firstSample = Samples.Find(s => s.Name == SampleInfo.HIT_NORMAL)
                                       ?? Samples.FirstOrDefault(); // TODO: remove this when guaranteed sort is present for samples (https://github.com/ppy/osu/issues/1933)
                     var sampleList = new List<SampleInfo>();
 
diff --git a/osu.Game.Rulesets.Taiko/Objects/Drawables/DrawableSwell.cs b/osu.Game.Rulesets.Taiko/Objects/Drawables/DrawableSwell.cs
index 1412bd3cea..153e5733e5 100644
--- a/osu.Game.Rulesets.Taiko/Objects/Drawables/DrawableSwell.cs
+++ b/osu.Game.Rulesets.Taiko/Objects/Drawables/DrawableSwell.cs
@@ -135,7 +135,7 @@ namespace osu.Game.Rulesets.Taiko.Objects.Drawables
         {
             if (userTriggered)
             {
-                var nextTick = ticks.FirstOrDefault(j => !j.IsHit);
+                var nextTick = ticks.Find(j => !j.IsHit);
 
                 nextTick?.TriggerResult(HitResult.Great);
 
diff --git a/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs b/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
index db66c01814..f156728981 100644
--- a/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
+++ b/osu.Game.Tests/Visual/TestCaseBeatmapCarousel.cs
@@ -148,7 +148,7 @@ namespace osu.Game.Tests.Visual
 
         private bool selectedBeatmapVisible()
         {
-            var currentlySelected = carousel.Items.FirstOrDefault(s => s.Item is CarouselBeatmap && s.Item.State == CarouselItemState.Selected);
+            var currentlySelected = carousel.Items.Find(s => s.Item is CarouselBeatmap && s.Item.State == CarouselItemState.Selected);
             if (currentlySelected == null)
                 return true;
             return currentlySelected.Item.Visible;
diff --git a/osu.Game.Tests/Visual/TestCaseNotificationOverlay.cs b/osu.Game.Tests/Visual/TestCaseNotificationOverlay.cs
index 2c56f08f42..66ae2d3012 100644
--- a/osu.Game.Tests/Visual/TestCaseNotificationOverlay.cs
+++ b/osu.Game.Tests/Visual/TestCaseNotificationOverlay.cs
@@ -49,7 +49,6 @@ namespace osu.Game.Tests.Visual
 
             manager.UnreadCount.ValueChanged += count => { displayedCount.Text = $"displayed count: {count}"; };
 
-
             setState(Visibility.Visible);
             AddStep(@"simple #1", sendHelloNotification);
             AddStep(@"simple #2", sendAmazingNotification);
@@ -75,7 +74,6 @@ namespace osu.Game.Tests.Visual
 
             checkProgressingCount(0);
 
-
             setState(Visibility.Visible);
 
             //AddStep(@"barrage", () => sendBarrage());
@@ -111,7 +109,7 @@ namespace osu.Game.Tests.Visual
 
             if (progressingNotifications.Count(n => n.State == ProgressNotificationState.Active) < 3)
             {
-                var p = progressingNotifications.FirstOrDefault(n => n.State == ProgressNotificationState.Queued);
+                var p = progressingNotifications.Find(n => n.State == ProgressNotificationState.Queued);
                 if (p != null)
                     p.State = ProgressNotificationState.Active;
             }
diff --git a/osu.Game/Beatmaps/BeatmapSetInfo.cs b/osu.Game/Beatmaps/BeatmapSetInfo.cs
index 8c541e9344..a5399ce8c7 100644
--- a/osu.Game/Beatmaps/BeatmapSetInfo.cs
+++ b/osu.Game/Beatmaps/BeatmapSetInfo.cs
@@ -36,7 +36,7 @@ namespace osu.Game.Beatmaps
 
         public string Hash { get; set; }
 
-        public string StoryboardFile => Files?.FirstOrDefault(f => f.Filename.EndsWith(".osb"))?.Filename;
+        public string StoryboardFile => Files?.Find(f => f.Filename.EndsWith(".osb"))?.Filename;
 
         public List<BeatmapSetFileInfo> Files { get; set; }
 
diff --git a/osu.Game/Configuration/DatabasedConfigManager.cs b/osu.Game/Configuration/DatabasedConfigManager.cs
index 0ede6de0f2..334fed2b5a 100644
--- a/osu.Game/Configuration/DatabasedConfigManager.cs
+++ b/osu.Game/Configuration/DatabasedConfigManager.cs
@@ -2,7 +2,6 @@
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System.Collections.Generic;
-using System.Linq;
 using osu.Framework.Configuration;
 using osu.Game.Rulesets;
 
@@ -43,7 +42,7 @@ namespace osu.Game.Configuration
         {
             base.AddBindable(lookup, bindable);
 
-            var setting = databasedSettings.FirstOrDefault(s => (int)s.Key == (int)(object)lookup);
+            var setting = databasedSettings.Find(s => (int)s.Key == (int)(object)lookup);
             if (setting != null)
             {
                 bindable.Parse(setting.Value);
diff --git a/osu.Game/OsuGame.cs b/osu.Game/OsuGame.cs
index 2a4c812401..702b1ae108 100644
--- a/osu.Game/OsuGame.cs
+++ b/osu.Game/OsuGame.cs
@@ -222,7 +222,7 @@ namespace osu.Game
                 var databasedSet = BeatmapManager.QueryBeatmapSet(s => s.OnlineBeatmapSetID == beatmap.OnlineBeatmapSetID);
 
                 // Use first beatmap available for current ruleset, else switch ruleset.
-                var first = databasedSet.Beatmaps.FirstOrDefault(b => b.Ruleset == ruleset.Value) ?? databasedSet.Beatmaps.First();
+                var first = databasedSet.Beatmaps.Find(b => b.Ruleset == ruleset.Value) ?? databasedSet.Beatmaps.First();
 
                 ruleset.Value = first.Ruleset;
                 Beatmap.Value = BeatmapManager.GetWorkingBeatmap(first);
diff --git a/osu.Game/Screens/Edit/EditorClock.cs b/osu.Game/Screens/Edit/EditorClock.cs
index aa30b1a9f5..05ba1ab732 100644
--- a/osu.Game/Screens/Edit/EditorClock.cs
+++ b/osu.Game/Screens/Edit/EditorClock.cs
@@ -57,7 +57,7 @@ namespace osu.Game.Screens.Edit
 
             // Depending on beatSnapLength, we may snap to a beat that is beyond timingPoint's end time, but we want to instead snap to
             // the next timing point's start time
-            var nextTimingPoint = ControlPointInfo.TimingPoints.FirstOrDefault(t => t.Time > timingPoint.Time);
+            var nextTimingPoint = ControlPointInfo.TimingPoints.Find(t => t.Time > timingPoint.Time);
             if (position > nextTimingPoint?.Time)
                 position = nextTimingPoint.Time;
 
@@ -123,7 +123,7 @@ namespace osu.Game.Screens.Edit
             if (seekTime < timingPoint.Time && timingPoint != ControlPointInfo.TimingPoints.First())
                 seekTime = timingPoint.Time;
 
-            var nextTimingPoint = ControlPointInfo.TimingPoints.FirstOrDefault(t => t.Time > timingPoint.Time);
+            var nextTimingPoint = ControlPointInfo.TimingPoints.Find(t => t.Time > timingPoint.Time);
             if (seekTime > nextTimingPoint?.Time)
                 seekTime = nextTimingPoint.Time;
 
diff --git a/osu.Game/Screens/Tournament/Drawings.cs b/osu.Game/Screens/Tournament/Drawings.cs
index 0a428ea289..754f34f00f 100644
--- a/osu.Game/Screens/Tournament/Drawings.cs
+++ b/osu.Game/Screens/Tournament/Drawings.cs
@@ -327,7 +327,7 @@ namespace osu.Game.Screens.Tournament
                                 continue;
 
                             // ReSharper disable once AccessToModifiedClosure
-                            DrawingsTeam teamToAdd = allTeams.FirstOrDefault(t => t.FullName == line);
+                            DrawingsTeam teamToAdd = allTeams.Find(t => t.FullName == line);
 
                             if (teamToAdd == null)
                                 continue;
diff --git a/osu.Game/Skinning/LegacySkin.cs b/osu.Game/Skinning/LegacySkin.cs
index 25a9813ad6..23367c58c9 100644
--- a/osu.Game/Skinning/LegacySkin.cs
+++ b/osu.Game/Skinning/LegacySkin.cs
@@ -102,7 +102,7 @@ namespace osu.Game.Skinning
 
                 string lastPiece = filename.Split('/').Last();
 
-                var file = source.Files.FirstOrDefault(f =>
+                var file = source.Files.Find(f =>
                     string.Equals(hasExtension ? f.Filename : Path.ChangeExtension(f.Filename, null), lastPiece, StringComparison.InvariantCultureIgnoreCase));
                 return file?.FileInfo.StoragePath;
             }
diff --git a/osu.Game/Storyboards/Drawables/DrawableStoryboardAnimation.cs b/osu.Game/Storyboards/Drawables/DrawableStoryboardAnimation.cs
index 8f860c5f53..2330c25443 100644
--- a/osu.Game/Storyboards/Drawables/DrawableStoryboardAnimation.cs
+++ b/osu.Game/Storyboards/Drawables/DrawableStoryboardAnimation.cs
@@ -6,7 +6,6 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Animations;
 using osu.Framework.Graphics.Textures;
-using System.Linq;
 using osu.Game.Beatmaps;
 
 namespace osu.Game.Storyboards.Drawables
@@ -71,7 +70,7 @@ namespace osu.Game.Storyboards.Drawables
             {
                 var framePath = basePath.Replace(".", frame + ".");
 
-                var path = beatmap.Value.BeatmapSetInfo.Files.FirstOrDefault(f => f.Filename.ToLowerInvariant() == framePath)?.FileInfo.StoragePath;
+                var path = beatmap.Value.BeatmapSetInfo.Files.Find(f => f.Filename.ToLowerInvariant() == framePath)?.FileInfo.StoragePath;
                 if (path == null)
                     continue;
 
diff --git a/osu.Game/Storyboards/Drawables/DrawableStoryboardSprite.cs b/osu.Game/Storyboards/Drawables/DrawableStoryboardSprite.cs
index 485f9bf61c..b03285b419 100644
--- a/osu.Game/Storyboards/Drawables/DrawableStoryboardSprite.cs
+++ b/osu.Game/Storyboards/Drawables/DrawableStoryboardSprite.cs
@@ -6,7 +6,6 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.Textures;
-using System.Linq;
 using osu.Game.Beatmaps;
 
 namespace osu.Game.Storyboards.Drawables
@@ -66,7 +65,7 @@ namespace osu.Game.Storyboards.Drawables
         private void load(IBindableBeatmap beatmap, TextureStore textureStore)
         {
             var spritePath = Sprite.Path.ToLowerInvariant();
-            var path = beatmap.Value.BeatmapSetInfo.Files.FirstOrDefault(f => f.Filename.ToLowerInvariant() == spritePath)?.FileInfo.StoragePath;
+            var path = beatmap.Value.BeatmapSetInfo.Files.Find(f => f.Filename.ToLowerInvariant() == spritePath)?.FileInfo.StoragePath;
             if (path == null)
                 return;