diff --git a/client/commonFramework/code-uri.js b/client/commonFramework/code-uri.js
index a0694b892b..3051c12bd2 100644
--- a/client/commonFramework/code-uri.js
+++ b/client/commonFramework/code-uri.js
@@ -42,6 +42,8 @@ window.common = (function(global) {
       return decoded
         .split('?')
         .splice(1)
+        .pop()
+        .split('&')
         .reduce(function(found, param) {
           var key = param.split('=')[0];
           if (key === 'solution') {
@@ -55,6 +57,23 @@ window.common = (function(global) {
         codeUri.isInQuery(location.search) ||
         codeUri.isInQuery(location.hash);
     },
+    getKeyInQuery(query, keyToFind = '') {
+      return query
+        .split('&')
+        .reduce(function(oldValue, param) {
+          var key = param.split('=')[0];
+          var value = param.split('=')[1];
+          if (key === keyToFind) {
+            return value;
+          }
+          return oldValue;
+        }, null);
+    },
+    getSolutionFromQuery(query = '') {
+      return decodeFcc(
+        codeUri.decode(codeUri.getKeyInQuery(query, 'solution'))
+      );
+    },
     parse: function() {
       if (!codeUri.enabled) {
         return null;
@@ -62,6 +81,7 @@ window.common = (function(global) {
       var query;
       if (location.search && codeUri.isInQuery(location.search)) {
         query = location.search.replace(/^\?/, '');
+
         if (history && typeof history.replaceState === 'function') {
           history.replaceState(
             history.state,
@@ -73,30 +93,29 @@ window.common = (function(global) {
       } else {
         query = location.hash.replace(/^\#\?/, '');
       }
+
       if (!query) {
         return null;
       }
 
-      return query
-        .split('&')
-        .reduce(function(solution, param) {
-          var key = param.split('=')[0];
-          var value = param.split('=')[1];
-          if (key === 'solution') {
-            return decodeFcc(codeUri.decode(value || ''));
-          }
-          return solution;
-        }, null);
+      return this.getSolutionFromQuery(query);
     },
     querify: function(solution) {
       if (!codeUri.enabled) {
         return null;
       }
       if (history && typeof history.replaceState === 'function') {
+        // grab the url up to the query
+        // destroy any hash symbols still clinging to life
+        const url = (location.href.split('?')[0]).replace(/(#*)$/, '');
         history.replaceState(
           history.state,
           null,
-          '?solution=' + codeUri.encode(encodeFcc(solution))
+          url +
+            '#?' +
+            (codeUri.shouldRun() ? '' : 'run=disabled&') +
+            'solution=' +
+            codeUri.encode(encodeFcc(solution))
         );
       } else {
         location.hash = '?solution=' +
@@ -105,7 +124,13 @@ window.common = (function(global) {
 
       return solution;
     },
-    enabled: true
+    enabled: true,
+    shouldRun() {
+      return !this.getKeyInQuery(
+        (location.search || location.hash).replace(/^(\?|#\?)/, ''),
+        'run'
+      );
+    }
   };
 
   common.init.push(function() {
@@ -113,6 +138,7 @@ window.common = (function(global) {
   });
 
   common.codeUri = codeUri;
+  common.shouldRun = () => codeUri.shouldRun();
 
   return common;
 }(window));
diff --git a/client/commonFramework/update-preview.js b/client/commonFramework/update-preview.js
index 0f483a6a9c..ab99e46a6f 100644
--- a/client/commonFramework/update-preview.js
+++ b/client/commonFramework/update-preview.js
@@ -34,6 +34,11 @@ window.common = (function(global) {
   body { padding: 0px 3px 0px 3px; }
 </style>
   `;
+  const codeDisabledError = `
+    <script>
+      window.__err = new Error('code has been disabled');
+    </script>
+  `;
 
   const iFrameScript$ =
     common.getScriptContent$('/js/iFrameScripts.js').shareReplay();
@@ -74,7 +79,7 @@ window.common = (function(global) {
         preview.write(
           libraryIncludes +
           jQuery +
-          code +
+          (common.shouldRun() ? code : codeDisabledError) +
           '<!-- -->' +
           iframeScript
         );
diff --git a/client/iFrameScripts.js b/client/iFrameScripts.js
index 2fc6ac8b69..e9d1456f88 100644
--- a/client/iFrameScripts.js
+++ b/client/iFrameScripts.js
@@ -11,6 +11,9 @@ window.$(document).ready(function() {
   var common = parent.common;
 
   common.getJsOutput = function evalJs(code = '') {
+    if (window.__err || !common.shouldRun()) {
+      return window.__err || 'code disabled';
+    }
     let output;
     try {
       /* eslint-disable no-eval */
diff --git a/public/js/lib/loop-protect/loop-protect.js b/public/js/lib/loop-protect/loop-protect.js
index 5050605b9e..1452d9525d 100644
--- a/public/js/lib/loop-protect/loop-protect.js
+++ b/public/js/lib/loop-protect/loop-protect.js
@@ -20,6 +20,7 @@ if (typeof DEBUG === 'undefined') { DEBUG = true; }
   var reSingle = /\b(for|while|do)\b/;
   var labelRe = /\b([a-z_]{1}\w+:)/i;
   var comments = /(?:\/\*(?:[\s\S]*?)\*\/)|(?:([\s;])+\/\/(?:.*)$)/gm;
+  var loopTimeout = 500;
 
   var loopProtect = rewriteLoops;
 
@@ -404,8 +405,7 @@ if (typeof DEBUG === 'undefined') { DEBUG = true; }
     }
 
     line.hit++;
-    if ((now - line.time) > 100) {//} && line.hit !== line.last+1) {
-      // We've spent over 100ms on this loop... smells infinite.
+    if ((now - line.time) > loopTimeout) {//} && line.hit !== line.last+1) {
       loopProtect.hit(state.line);
       // Returning true prevents the loop running again
       return true;