diff --git a/build/study.dev.js b/build/study.dev.js
index 3ed0118..4d8a758 100644
--- a/build/study.dev.js
+++ b/build/study.dev.js
@@ -1,6 +1,6 @@
 /**
   studyjs - A client side A/B tester
-  @version v5.0.2
+  @version v5.0.3
   @link https://github.com/dollarshaveclub/study
   @author Jacob Kelley <jacob.kelley@dollarshaveclub.com>
   @license MIT
@@ -37,7 +37,7 @@
   var getDefaultBucket = function getDefaultBucket(buckets) {
     var defaultBuckets = Object.keys(buckets).filter(function (name) {
       var x = buckets[name];
-      return x.default || x.winner;
+      return x["default"] || x.winner;
     });
     return defaultBuckets[0] || Object.keys(buckets)[0];
   };
@@ -112,37 +112,43 @@
     };
 
     _proto.removeClasses = function removeClasses(testName, exceptClassName) {
-      var root = this.root;
-      if (!root) return; // classList does not support returning all classes
-
-      var currentClassNames = root.className.split(/\s+/g).map(function (x) {
-        return x.trim();
-      }).filter(Boolean);
-      currentClassNames.filter(function (x) {
-        return x.indexOf(testName + "--") === 0;
-      }).filter(function (className) {
-        return className !== exceptClassName;
-      }).forEach(function (className) {
-        return root.classList.remove(className);
-      });
+      try {
+        var root = this.root;
+        if (!root) return; // classList does not support returning all classes
+
+        var currentClassNames = root.className.split(/\s+/g).map(function (x) {
+          return x.trim();
+        }).filter(Boolean);
+        currentClassNames.filter(function (x) {
+          return x.indexOf(testName + "--") === 0;
+        }).filter(function (className) {
+          return className !== exceptClassName;
+        }).forEach(function (className) {
+          return root.classList.remove(className);
+        });
+      } catch (_) {// Ignore
+      }
     };
 
     _proto.applyClasses = function applyClasses() {
       var _this2 = this;
 
-      var userAssignments = this.userAssignments,
-          root = this.root;
-      if (!root) return;
-      Object.keys(userAssignments).forEach(function (testName) {
-        var bucket = userAssignments[testName];
-        var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
+      try {
+        var userAssignments = this.userAssignments,
+            root = this.root;
+        if (!root) return;
+        Object.keys(userAssignments).forEach(function (testName) {
+          var bucket = userAssignments[testName];
+          var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
 
-        _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
-        // this removes then adds a class, which is not ideal but is clean
+          _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
+          // this removes then adds a class, which is not ideal but is clean
 
 
-        if (className) root.classList.add(className);
-      });
+          if (className) root.classList.add(className);
+        });
+      } catch (_) {// Ignore
+      }
     };
 
     _proto.assignAll = function assignAll() {
diff --git a/build/study.es.js b/build/study.es.js
index 3376ada..752f01d 100644
--- a/build/study.es.js
+++ b/build/study.es.js
@@ -1,6 +1,6 @@
 /**
   studyjs - A client side A/B tester
-  @version v5.0.2
+  @version v5.0.3
   @link https://github.com/dollarshaveclub/study
   @author Jacob Kelley <jacob.kelley@dollarshaveclub.com>
   @license MIT
@@ -31,7 +31,7 @@ var chooseWeightedItem = function chooseWeightedItem(names, weights) {
 var getDefaultBucket = function getDefaultBucket(buckets) {
   var defaultBuckets = Object.keys(buckets).filter(function (name) {
     var x = buckets[name];
-    return x.default || x.winner;
+    return x["default"] || x.winner;
   });
   return defaultBuckets[0] || Object.keys(buckets)[0];
 };
@@ -106,37 +106,43 @@ function () {
   };
 
   _proto.removeClasses = function removeClasses(testName, exceptClassName) {
-    var root = this.root;
-    if (!root) return; // classList does not support returning all classes
-
-    var currentClassNames = root.className.split(/\s+/g).map(function (x) {
-      return x.trim();
-    }).filter(Boolean);
-    currentClassNames.filter(function (x) {
-      return x.indexOf(testName + "--") === 0;
-    }).filter(function (className) {
-      return className !== exceptClassName;
-    }).forEach(function (className) {
-      return root.classList.remove(className);
-    });
+    try {
+      var root = this.root;
+      if (!root) return; // classList does not support returning all classes
+
+      var currentClassNames = root.className.split(/\s+/g).map(function (x) {
+        return x.trim();
+      }).filter(Boolean);
+      currentClassNames.filter(function (x) {
+        return x.indexOf(testName + "--") === 0;
+      }).filter(function (className) {
+        return className !== exceptClassName;
+      }).forEach(function (className) {
+        return root.classList.remove(className);
+      });
+    } catch (_) {// Ignore
+    }
   };
 
   _proto.applyClasses = function applyClasses() {
     var _this2 = this;
 
-    var userAssignments = this.userAssignments,
-        root = this.root;
-    if (!root) return;
-    Object.keys(userAssignments).forEach(function (testName) {
-      var bucket = userAssignments[testName];
-      var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
+    try {
+      var userAssignments = this.userAssignments,
+          root = this.root;
+      if (!root) return;
+      Object.keys(userAssignments).forEach(function (testName) {
+        var bucket = userAssignments[testName];
+        var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
 
-      _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
-      // this removes then adds a class, which is not ideal but is clean
+        _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
+        // this removes then adds a class, which is not ideal but is clean
 
 
-      if (className) root.classList.add(className);
-    });
+        if (className) root.classList.add(className);
+      });
+    } catch (_) {// Ignore
+    }
   };
 
   _proto.assignAll = function assignAll() {
diff --git a/build/study.js b/build/study.js
index 3ed0118..4d8a758 100644
--- a/build/study.js
+++ b/build/study.js
@@ -1,6 +1,6 @@
 /**
   studyjs - A client side A/B tester
-  @version v5.0.2
+  @version v5.0.3
   @link https://github.com/dollarshaveclub/study
   @author Jacob Kelley <jacob.kelley@dollarshaveclub.com>
   @license MIT
@@ -37,7 +37,7 @@
   var getDefaultBucket = function getDefaultBucket(buckets) {
     var defaultBuckets = Object.keys(buckets).filter(function (name) {
       var x = buckets[name];
-      return x.default || x.winner;
+      return x["default"] || x.winner;
     });
     return defaultBuckets[0] || Object.keys(buckets)[0];
   };
@@ -112,37 +112,43 @@
     };
 
     _proto.removeClasses = function removeClasses(testName, exceptClassName) {
-      var root = this.root;
-      if (!root) return; // classList does not support returning all classes
-
-      var currentClassNames = root.className.split(/\s+/g).map(function (x) {
-        return x.trim();
-      }).filter(Boolean);
-      currentClassNames.filter(function (x) {
-        return x.indexOf(testName + "--") === 0;
-      }).filter(function (className) {
-        return className !== exceptClassName;
-      }).forEach(function (className) {
-        return root.classList.remove(className);
-      });
+      try {
+        var root = this.root;
+        if (!root) return; // classList does not support returning all classes
+
+        var currentClassNames = root.className.split(/\s+/g).map(function (x) {
+          return x.trim();
+        }).filter(Boolean);
+        currentClassNames.filter(function (x) {
+          return x.indexOf(testName + "--") === 0;
+        }).filter(function (className) {
+          return className !== exceptClassName;
+        }).forEach(function (className) {
+          return root.classList.remove(className);
+        });
+      } catch (_) {// Ignore
+      }
     };
 
     _proto.applyClasses = function applyClasses() {
       var _this2 = this;
 
-      var userAssignments = this.userAssignments,
-          root = this.root;
-      if (!root) return;
-      Object.keys(userAssignments).forEach(function (testName) {
-        var bucket = userAssignments[testName];
-        var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
+      try {
+        var userAssignments = this.userAssignments,
+            root = this.root;
+        if (!root) return;
+        Object.keys(userAssignments).forEach(function (testName) {
+          var bucket = userAssignments[testName];
+          var className = bucket ? testName + "--" + bucket : null; // remove all classes related to this bucket
 
-        _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
-        // this removes then adds a class, which is not ideal but is clean
+          _this2.removeClasses(testName, className); // only assign a class is the test is assigned to a bucket
+          // this removes then adds a class, which is not ideal but is clean
 
 
-        if (className) root.classList.add(className);
-      });
+          if (className) root.classList.add(className);
+        });
+      } catch (_) {// Ignore
+      }
     };
 
     _proto.assignAll = function assignAll() {
diff --git a/build/study.min.js b/build/study.min.js
index 44b2113..b2029e1 100644
--- a/build/study.min.js
+++ b/build/study.min.js
@@ -1,8 +1,8 @@
 /**
   studyjs - A client side A/B tester
-  @version v5.0.2
+  @version v5.0.3
   @link https://github.com/dollarshaveclub/study
   @author Jacob Kelley <jacob.kelley@dollarshaveclub.com>
   @license MIT
 **/
-!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):(e=e||self).Study=t()}(this,function(){"use strict";var s,t=function(e,t){if(e.length!==t.length)throw new Error("names and weights must have equal length!");for(var s,n,r=t.reduce(function(e,t){return e+t},0),i=0,o=(s=0,n=r,Math.random()*(n-s)+s),u=0;u<e.length;u++)if(o<=(i+=t[u]))return e[u];return e[e.length-1]},c=function(s){var e=Object.keys(s.buckets),n=[];return e.forEach(function(e){var t=s.buckets[e].weight;null==t&&(t=1),n.push(t)}),t(e,n)},e=function(){function e(e){void 0===e&&(e={}),Object.assign(this,{storageKey:"ab-tests",root:"undefined"!=typeof document?document.body:null},e),function(e){if(!e)throw new Error("You must supply a store!");if("function"!=typeof e.get)throw new Error("The store must implement .get()");if("function"!=typeof e.set)throw new Error("The store must implement .set()");if("function"!=typeof e.isSupported)throw new Error("The store must implement .isSupported()");if(!e.isSupported())throw new Error("The store is not supported.")}(this.store),this.previousAssignments={};try{var t=this.store.get(this.storageKey);"string"==typeof t&&"{"===t[0]&&(this.previousAssignments=JSON.parse(t))}catch(e){}this.userAssignments={},this.persistedUserAssignments={},this.providedTests=[]}var t=e.prototype;return t.define=function(e){var t=this,s=e;Array.isArray(e)||(s=[e]),s.forEach(function(e){if(!e.name)throw new Error("Tests must have a name");if(!e.buckets)throw new Error("Tests must have buckets");if(!Object.keys(e.buckets))throw new Error("Tests must have buckets");t.providedTests.push(e)})},t.definitions=function(){return this.providedTests},t.removeClasses=function(t,s){var n=this.root;n&&n.className.split(/\s+/g).map(function(e){return e.trim()}).filter(Boolean).filter(function(e){return 0===e.indexOf(t+"--")}).filter(function(e){return e!==s}).forEach(function(e){return n.classList.remove(e)})},t.applyClasses=function(){var n=this,r=this.userAssignments,i=this.root;i&&Object.keys(r).forEach(function(e){var t=r[e],s=t?e+"--"+t:null;n.removeClasses(e,s),s&&i.classList.add(s)})},t.assignAll=function(){var o=this.previousAssignments,u=this.userAssignments,a=this.persistedUserAssignments;this.providedTests.forEach(function(t){var e=Object.keys(t.buckets).filter(function(e){return t.buckets[e].winner})[0];if(e)u[t.name]=e;else if(!u[t.name]){var s=o[t.name];if(s&&t.buckets[s]){var n=o[t.name];return a[t.name]=n,u[t.name]=n,void(t.active=!0)}if(!1!==t.active){var r,i=c(t);a[t.name]=i,u[t.name]=i}else u[t.name]=(r=t.buckets,Object.keys(r).filter(function(e){var t=r[e];return t.default||t.winner})[0]||Object.keys(r)[0])}}),this.persist(),this.applyClasses()},t.assign=function(t,e){if(!t)return this.assignAll();var s=this.providedTests.filter(function(e){return e.name===t})[0];if(null===e||!s)return delete this.userAssignments[t],delete this.persistedUserAssignments[t],this.persist(),void this.removeClasses(t);var n=e||c(s);this.userAssignments[t]=n,this.persistedUserAssignments[t]=n,s.active=!0,this.persist(),this.applyClasses()},t.extendAssignments=function(e){return e},t.assignments=function(){return this.extendAssignments(this.userAssignments)},t.persist=function(){this.store.set(this.storageKey,JSON.stringify(this.persistedUserAssignments))},e}(),n={browserCookie:{type:"browserCookie",get:function(e){return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*"+encodeURIComponent(e).replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=\\s*([^;]*).*$)|^.*$"),"$1"))||null},set:function(e,t){var s=new Date("12/31/9999").toUTCString();document.cookie=encodeURIComponent(e)+"="+encodeURIComponent(t)+"; expires="+s+"; path=/"},isSupported:function(){return"undefined"!=typeof document}},local:{type:"local",get:function(e){return localStorage.getItem(e)},set:function(e,t){return localStorage.setItem(e,t)},isSupported:function(){if("undefined"!=typeof localStorage)return!0;var e=new Date;try{return localStorage.setItem(e,e),localStorage.removeItem(e),!0}catch(e){return!1}}},memory:(s=Object.create(null),{type:"memory",get:function(e){return s[e]},set:function(e,t){s[e]=t},isSupported:function(){return!0}})};return(window.Study=e).stores=n,e});
+!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):(e=e||self).Study=t()}(this,function(){"use strict";var s,t=function(e,t){if(e.length!==t.length)throw new Error("names and weights must have equal length!");for(var s=0,n=function(e,t){return Math.random()*(t-e)+e}(0,t.reduce(function(e,t){return e+t},0)),r=0;r<e.length;r++)if(n<=(s+=t[r]))return e[r];return e[e.length-1]},a=function(s){var e=Object.keys(s.buckets),n=[];return e.forEach(function(e){var t=s.buckets[e].weight;null==t&&(t=1),n.push(t)}),t(e,n)},e=function(){function e(e){void 0===e&&(e={}),Object.assign(this,{storageKey:"ab-tests",root:"undefined"!=typeof document?document.body:null},e),function(e){if(!e)throw new Error("You must supply a store!");if("function"!=typeof e.get)throw new Error("The store must implement .get()");if("function"!=typeof e.set)throw new Error("The store must implement .set()");if("function"!=typeof e.isSupported)throw new Error("The store must implement .isSupported()");if(!e.isSupported())throw new Error("The store is not supported.")}(this.store),this.previousAssignments={};try{var t=this.store.get(this.storageKey);"string"==typeof t&&"{"===t[0]&&(this.previousAssignments=JSON.parse(t))}catch(e){}this.userAssignments={},this.persistedUserAssignments={},this.providedTests=[]}var t=e.prototype;return t.define=function(e){var t=this,s=e;Array.isArray(e)||(s=[e]),s.forEach(function(e){if(!e.name)throw new Error("Tests must have a name");if(!e.buckets)throw new Error("Tests must have buckets");if(!Object.keys(e.buckets))throw new Error("Tests must have buckets");t.providedTests.push(e)})},t.definitions=function(){return this.providedTests},t.removeClasses=function(t,s){try{var n=this.root;if(!n)return;n.className.split(/\s+/g).map(function(e){return e.trim()}).filter(Boolean).filter(function(e){return 0===e.indexOf(t+"--")}).filter(function(e){return e!==s}).forEach(function(e){return n.classList.remove(e)})}catch(e){}},t.applyClasses=function(){var n=this;try{var r=this.userAssignments,i=this.root;if(!i)return;Object.keys(r).forEach(function(e){var t=r[e],s=t?e+"--"+t:null;n.removeClasses(e,s),s&&i.classList.add(s)})}catch(e){}},t.assignAll=function(){var i=this.previousAssignments,o=this.userAssignments,u=this.persistedUserAssignments;this.providedTests.forEach(function(t){var e=Object.keys(t.buckets).filter(function(e){return t.buckets[e].winner})[0];if(e)o[t.name]=e;else if(!o[t.name]){var s=i[t.name];if(s&&t.buckets[s]){var n=i[t.name];return u[t.name]=n,o[t.name]=n,void(t.active=!0)}if(!1!==t.active){var r=a(t);u[t.name]=r,o[t.name]=r}else o[t.name]=function(s){return Object.keys(s).filter(function(e){var t=s[e];return t.default||t.winner})[0]||Object.keys(s)[0]}(t.buckets)}}),this.persist(),this.applyClasses()},t.assign=function(t,e){if(!t)return this.assignAll();var s=this.providedTests.filter(function(e){return e.name===t})[0];if(null===e||!s)return delete this.userAssignments[t],delete this.persistedUserAssignments[t],this.persist(),void this.removeClasses(t);var n=e||a(s);this.userAssignments[t]=n,this.persistedUserAssignments[t]=n,s.active=!0,this.persist(),this.applyClasses()},t.extendAssignments=function(e){return e},t.assignments=function(){return this.extendAssignments(this.userAssignments)},t.persist=function(){this.store.set(this.storageKey,JSON.stringify(this.persistedUserAssignments))},e}(),n={browserCookie:{type:"browserCookie",get:function(e){return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*"+encodeURIComponent(e).replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=\\s*([^;]*).*$)|^.*$"),"$1"))||null},set:function(e,t){var s=new Date("12/31/9999").toUTCString();document.cookie=encodeURIComponent(e)+"="+encodeURIComponent(t)+"; expires="+s+"; path=/"},isSupported:function(){return"undefined"!=typeof document}},local:{type:"local",get:function(e){return localStorage.getItem(e)},set:function(e,t){return localStorage.setItem(e,t)},isSupported:function(){if("undefined"!=typeof localStorage)return!0;var e=new Date;try{return localStorage.setItem(e,e),localStorage.removeItem(e),!0}catch(e){return!1}}},memory:(s=Object.create(null),{type:"memory",get:function(e){return s[e]},set:function(e,t){s[e]=t},isSupported:function(){return!0}})};return(window.Study=e).stores=n,e});
diff --git a/package.json b/package.json
index 41d2824..77cd60c 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "studyjs",
-  "version": "5.0.2",
+  "version": "5.0.3",
   "author": "Jacob Kelley <jacob.kelley@dollarshaveclub.com>",
   "homepage": "https://github.com/dollarshaveclub/study",
   "description": "A client side A/B tester",
diff --git a/src/study.js b/src/study.js
index e94a981..18cdbea 100644
--- a/src/study.js
+++ b/src/study.js
@@ -49,35 +49,43 @@ export default class Study {
   }
 
   removeClasses (testName, exceptClassName) {
-    const { root } = this
-    if (!root) return
-
-    // classList does not support returning all classes
-    const currentClassNames = root.className.split(/\s+/g)
-      .map(x => x.trim())
-      .filter(Boolean)
-
-    currentClassNames
-      .filter(x => x.indexOf(`${testName}--`) === 0)
-      .filter(className => className !== exceptClassName)
-      .forEach(className => root.classList.remove(className))
+    try {
+      const { root } = this
+      if (!root) return
+
+      // classList does not support returning all classes
+      const currentClassNames = root.className.split(/\s+/g)
+        .map(x => x.trim())
+        .filter(Boolean)
+
+      currentClassNames
+        .filter(x => x.indexOf(`${testName}--`) === 0)
+        .filter(className => className !== exceptClassName)
+        .forEach(className => root.classList.remove(className))
+    } catch (_) {
+      // Ignore
+    }
   }
 
   applyClasses () {
-    const { userAssignments, root } = this
-    if (!root) return
+    try {
+      const { userAssignments, root } = this
+      if (!root) return
 
-    Object.keys(userAssignments).forEach((testName) => {
-      const bucket = userAssignments[testName]
+      Object.keys(userAssignments).forEach((testName) => {
+        const bucket = userAssignments[testName]
 
-      const className = bucket ? `${testName}--${bucket}` : null
-      // remove all classes related to this bucket
-      this.removeClasses(testName, className)
+        const className = bucket ? `${testName}--${bucket}` : null
+        // remove all classes related to this bucket
+        this.removeClasses(testName, className)
 
-      // only assign a class is the test is assigned to a bucket
-      // this removes then adds a class, which is not ideal but is clean
-      if (className) root.classList.add(className)
-    })
+        // only assign a class is the test is assigned to a bucket
+        // this removes then adds a class, which is not ideal but is clean
+        if (className) root.classList.add(className)
+      })
+    } catch (_) {
+      // Ignore
+    }
   }
 
   assignAll () {