diff --git a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
index 262f1c67ed..be670936fd 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs
@@ -34,6 +34,8 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
 
         public ManiaBeatmapConverter(bool isForCurrentRuleset, int availableColumns)
         {
+            if (availableColumns <= 0) throw new ArgumentOutOfRangeException(nameof(availableColumns));
+
             this.isForCurrentRuleset = isForCurrentRuleset;
             this.availableColumns = availableColumns;
         }
diff --git a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs
index 0716671da3..077b926635 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs
@@ -23,6 +23,9 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         public HitObjectPatternGenerator(FastRandom random, HitObject hitObject, Beatmap beatmap, int availableColumns, Pattern previousPattern, double previousTime, Vector2 previousPosition, double density, PatternType lastStair)
             : base(random, hitObject, beatmap, availableColumns, previousPattern)
         {
+            if (previousTime > hitObject.StartTime) throw new ArgumentOutOfRangeException(nameof(previousTime));
+            if (density < 0) throw new ArgumentOutOfRangeException(nameof(density));
+
             StairType = lastStair;
 
             TimingControlPoint timingPoint = beatmap.ControlPointInfo.TimingPointAt(hitObject.StartTime);
diff --git a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs
index d1b962bdd4..a3173f9784 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs
@@ -28,8 +28,12 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         protected PatternGenerator(FastRandom random, HitObject hitObject, Beatmap beatmap, int availableColumns, Pattern previousPattern)
             : base(hitObject, beatmap, availableColumns, previousPattern)
         {
-            Random = random;
+            if (random == null) throw new ArgumentNullException(nameof(random));
+            if (beatmap == null) throw new ArgumentNullException(nameof(beatmap));
+            if (availableColumns <= 0) throw new ArgumentOutOfRangeException(nameof(availableColumns));
+            if (previousPattern == null) throw new ArgumentNullException(nameof(previousPattern));
 
+            Random = random;
             RandomStart = AvailableColumns == 8 ? 1 : 0;
         }
 
@@ -62,6 +66,12 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         /// <returns>The amount of notes to be generated.</returns>
         protected int GetRandomNoteCount(double p2, double p3, double p4 = 0, double p5 = 0, double p6 = 0)
         {
+            if (p2 < 0 || p2 > 1) throw new ArgumentOutOfRangeException(nameof(p2));
+            if (p3 < 0 || p3 > 1) throw new ArgumentOutOfRangeException(nameof(p3));
+            if (p4 < 0 || p4 > 1) throw new ArgumentOutOfRangeException(nameof(p4));
+            if (p5 < 0 || p5 > 1) throw new ArgumentOutOfRangeException(nameof(p5));
+            if (p6 < 0 || p6 > 1) throw new ArgumentOutOfRangeException(nameof(p6));
+
             double val = Random.NextDouble();
             if (val >= 1 - p6)
                 return 6;
diff --git a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/PatternGenerator.cs b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/PatternGenerator.cs
index 4fe100df23..ef321232c8 100644
--- a/osu.Game.Rulesets.Mania/Beatmaps/Patterns/PatternGenerator.cs
+++ b/osu.Game.Rulesets.Mania/Beatmaps/Patterns/PatternGenerator.cs
@@ -1,6 +1,7 @@
 // Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Objects;
 
@@ -33,6 +34,11 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns
 
         protected PatternGenerator(HitObject hitObject, Beatmap beatmap, int availableColumns, Pattern previousPattern)
         {
+            if (hitObject == null) throw new ArgumentNullException(nameof(hitObject));
+            if (beatmap == null) throw new ArgumentNullException(nameof(beatmap));
+            if (availableColumns <= 0) throw new ArgumentOutOfRangeException(nameof(availableColumns));
+            if (previousPattern == null) throw new ArgumentNullException(nameof(previousPattern));
+
             HitObject = hitObject;
             Beatmap = beatmap;
             AvailableColumns = availableColumns;