diff --git a/.eslintignore b/.eslintignore
new file mode 100644
index 000000000..df49525be
--- /dev/null
+++ b/.eslintignore
@@ -0,0 +1 @@
+app/scripts/lib/extension-instance.js
diff --git a/.eslintrc b/.eslintrc
index e64b3e5be..d7cb8022e 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -23,7 +23,6 @@
   ],
 
   "globals": {
-    "chrome": true,
     "document": false,
     "navigator": false,
     "web3": true,
diff --git a/CHANGELOG.md b/CHANGELOG.md
index eed562b71..d1939570c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## Current Master
 
+- MetaMask now throws descriptive errors when apps try to use synchronous web3 methods.
+
+## 2.6.2 2016-07-20
+
 - Fixed bug that would prevent the plugin from reopening on the first try after receiving a new transaction while locked.
 - Fixed bug that would render 0 ETH as a non-exact amount.
 
diff --git a/app/manifest.json b/app/manifest.json
index d1a4a2f54..4cca79c72 100644
--- a/app/manifest.json
+++ b/app/manifest.json
@@ -1,7 +1,7 @@
 {
   "name": "__MSG_appName__",
   "short_name": "Metamask",
-  "version": "2.6.1",
+  "version": "2.6.2",
   "manifest_version": 2,
   "description": "__MSG_appDescription__",
   "icons": {
@@ -37,6 +37,11 @@
       "all_frames": false
     }
   ],
+  "applications": {
+    "gecko": {
+      "id": "MOZILLA_EXTENSION_ID"
+    }
+  },
   "permissions": [
     "notifications",
     "storage",
diff --git a/app/scripts/background.js b/app/scripts/background.js
index 801dc95cf..34c994ab7 100644
--- a/app/scripts/background.js
+++ b/app/scripts/background.js
@@ -9,6 +9,7 @@ const createMsgNotification = require('./lib/notifications.js').createMsgNotific
 const messageManager = require('./lib/message-manager')
 const setupMultiplex = require('./lib/stream-utils.js').setupMultiplex
 const MetamaskController = require('./metamask-controller')
+const extension = require('./lib/extension')
 
 const STORAGE_KEY = 'metamask-config'
 
@@ -65,7 +66,7 @@ function showUnconfirmedTx (txParams, txData, onTxDoneCb) {
 // connect to other contexts
 //
 
-chrome.runtime.onConnect.addListener(connectRemote)
+extension.runtime.onConnect.addListener(connectRemote)
 function connectRemote (remotePort) {
   var isMetaMaskInternalProcess = (remotePort.name === 'popup')
   var portStream = new PortStream(remotePort)
@@ -133,8 +134,8 @@ function updateBadge (state) {
   if (count) {
     label = String(count)
   }
-  chrome.browserAction.setBadgeText({ text: label })
-  chrome.browserAction.setBadgeBackgroundColor({ color: '#506F8B' })
+  extension.browserAction.setBadgeText({ text: label })
+  extension.browserAction.setBadgeBackgroundColor({ color: '#506F8B' })
 }
 
 function loadData () {
diff --git a/app/scripts/chromereload.js b/app/scripts/chromereload.js
index 283a131f1..cd85a8114 100644
--- a/app/scripts/chromereload.js
+++ b/app/scripts/chromereload.js
@@ -25,11 +25,12 @@
 //   if (e.data) {
 //     var data = JSON.parse(e.data);
 //     if (data && data.command === 'reload') {
-//       chrome.runtime.reload();
+//       extension.runtime.reload();
 //     }
 //   }
 // };
 
+const extension = require('./lib/extension')
 window.LiveReloadOptions = { host: 'localhost' };
 
 (function e (t, n, r) { function s (o, u) { if (!n[o]) { if (!t[o]) { var a = typeof require === 'function' && require; if (!u && a) return a(o, !0); if (i) return i(o, !0); var f = new Error("Cannot find module '" + o + "'"); throw f.code = 'MODULE_NOT_FOUND', f } var l = n[o] = {exports: {}}; t[o][0].call(l.exports, function (e) { var n = t[o][1][e]; return s(n ? n : e) }, l, l.exports, e, t, n, r) } return n[o].exports } var i = typeof require === 'function' && require; for (var o = 0; o < r.length; o++)s(r[o]); return s })({1: [function (require, module, exports) {
diff --git a/app/scripts/contentscript.js b/app/scripts/contentscript.js
index 60b37284e..0ffe93e3c 100644
--- a/app/scripts/contentscript.js
+++ b/app/scripts/contentscript.js
@@ -1,6 +1,7 @@
 const LocalMessageDuplexStream = require('./lib/local-message-stream.js')
 const PortStream = require('./lib/port-stream.js')
 const ObjectMultiplex = require('./lib/obj-multiplex')
+const extension = require('./lib/extension')
 
 if (shouldInjectWeb3()) {
   setupInjection()
@@ -10,7 +11,7 @@ if (shouldInjectWeb3()) {
 function setupInjection(){
   // inject in-page script
   var scriptTag = document.createElement('script')
-  scriptTag.src = chrome.extension.getURL('scripts/inpage.js')
+  scriptTag.src = extension.extension.getURL('scripts/inpage.js')
   scriptTag.onload = function () { this.parentNode.removeChild(this) }
   var container = document.head || document.documentElement
   // append as first child
@@ -25,7 +26,7 @@ function setupStreams(){
     target: 'inpage',
   })
   pageStream.on('error', console.error.bind(console))
-  var pluginPort = chrome.runtime.connect({name: 'contentscript'})
+  var pluginPort = extension.runtime.connect({name: 'contentscript'})
   var pluginStream = new PortStream(pluginPort)
   pluginStream.on('error', console.error.bind(console))
 
@@ -49,4 +50,4 @@ function setupStreams(){
 function shouldInjectWeb3(){
   var shouldInject = (window.location.href.indexOf('.pdf') === -1)
   return shouldInject
-}
\ No newline at end of file
+}
diff --git a/app/scripts/inpage.js b/app/scripts/inpage.js
index f5e54cd7b..055235671 100644
--- a/app/scripts/inpage.js
+++ b/app/scripts/inpage.js
@@ -53,9 +53,17 @@ var __define
 
 function cleanContextForImports () {
   __define = global.define
-  delete global.define
+  try {
+    delete global.define
+  } catch (_) {
+    console.warn('MetaMask - global.define could not be deleted.')
+  }
 }
 
 function restoreContextAfterImports () {
-  global.define = __define
+  try {
+    global.define = __define
+  } catch (_) {
+    console.warn('MetaMask - global.define could not be overwritten.')
+  }
 }
diff --git a/app/scripts/lib/extension-instance.js b/app/scripts/lib/extension-instance.js
new file mode 100644
index 000000000..eeab6c6d0
--- /dev/null
+++ b/app/scripts/lib/extension-instance.js
@@ -0,0 +1,38 @@
+const apis = [
+  'alarms',
+  'bookmarks',
+  'browserAction',
+  'commands',
+  'contextMenus',
+  'cookies',
+  'downloads',
+  'events',
+  'extension',
+  'extensionTypes',
+  'history',
+  'i18n',
+  'idle',
+  'notifications',
+  'pageAction',
+  'runtime',
+  'storage',
+  'tabs',
+  'webNavigation',
+  'webRequest',
+  'windows',
+]
+
+function Extension () {
+  const _this = this
+  let global = window
+
+  if (window.chrome) {
+    global = window.chrome
+  }
+
+  apis.forEach(function (api) {
+    _this[api] = global[api]
+  })
+}
+
+module.exports = Extension
diff --git a/app/scripts/lib/extension.js b/app/scripts/lib/extension.js
new file mode 100644
index 000000000..4b670490f
--- /dev/null
+++ b/app/scripts/lib/extension.js
@@ -0,0 +1,14 @@
+/* Extension.js
+ *
+ * A module for unifying browser differences in the WebExtension API.
+ *
+ * Initially implemented because Chrome hides all of their WebExtension API
+ * behind a global `chrome` variable, but we'd like to start grooming
+ * the code-base for cross-browser extension support.
+ *
+ * You can read more about the WebExtension API here:
+ * https://developer.mozilla.org/en-US/Add-ons/WebExtensions
+ */
+
+const Extension = require('./extension-instance')
+module.exports = new Extension()
diff --git a/app/scripts/lib/inpage-provider.js b/app/scripts/lib/inpage-provider.js
index 3b6ec154f..e387be895 100644
--- a/app/scripts/lib/inpage-provider.js
+++ b/app/scripts/lib/inpage-provider.js
@@ -107,7 +107,15 @@ function createSyncProvider (providerConfig) {
         syncProviderUrl = MetamaskConfig.network.default
     }
   }
-  return new HttpProvider(syncProviderUrl)
+
+  const provider = new HttpProvider(syncProviderUrl)
+  // Stubbing out the send method to throw on sync methods:
+  provider.send = function() {
+    var message = 'The MetaMask Web3 object does not support synchronous methods. See https://github.com/MetaMask/faq#all-async---think-of-metamask-as-a-light-client for details.'
+    throw new Error(message)
+  }
+
+  return provider
 }
 
 function remoteStoreWithLocalStorageCache (storageKey) {
diff --git a/app/scripts/lib/notifications.js b/app/scripts/lib/notifications.js
index b6590b0e5..6c1601df1 100644
--- a/app/scripts/lib/notifications.js
+++ b/app/scripts/lib/notifications.js
@@ -7,6 +7,7 @@ const h = require('react-hyperscript')
 const PendingTxDetails = require('../../../ui/app/components/pending-tx-details')
 const PendingMsgDetails = require('../../../ui/app/components/pending-msg-details')
 const MetaMaskUiCss = require('../../../ui/css')
+const extension = require('./extension')
 var notificationHandlers = {}
 
 const notifications = {
@@ -20,34 +21,34 @@ window.METAMASK_NOTIFIER = notifications
 setupListeners()
 
 function setupListeners () {
-  // guard for chrome bug https://github.com/MetaMask/metamask-plugin/issues/236
-  if (!chrome.notifications) return console.error('Chrome notifications API missing...')
+  // guard for extension bug https://github.com/MetaMask/metamask-plugin/issues/236
+  if (!extension.notifications) return console.error('Chrome notifications API missing...')
 
   // notification button press
-  chrome.notifications.onButtonClicked.addListener(function (notificationId, buttonIndex) {
+  extension.notifications.onButtonClicked.addListener(function (notificationId, buttonIndex) {
     var handlers = notificationHandlers[notificationId]
     if (buttonIndex === 0) {
       handlers.confirm()
     } else {
       handlers.cancel()
     }
-    chrome.notifications.clear(notificationId)
+    extension.notifications.clear(notificationId)
   })
 
   // notification teardown
-  chrome.notifications.onClosed.addListener(function (notificationId) {
+  extension.notifications.onClosed.addListener(function (notificationId) {
     delete notificationHandlers[notificationId]
   })
 }
 
 // creation helper
 function createUnlockRequestNotification (opts) {
-  // guard for chrome bug https://github.com/MetaMask/metamask-plugin/issues/236
-  if (!chrome.notifications) return console.error('Chrome notifications API missing...')
+  // guard for extension bug https://github.com/MetaMask/metamask-plugin/issues/236
+  if (!extension.notifications) return console.error('Chrome notifications API missing...')
   var message = 'An Ethereum app has requested a signature. Please unlock your account.'
 
   var id = createId()
-  chrome.notifications.create(id, {
+  extension.notifications.create(id, {
     type: 'basic',
     iconUrl: '/images/icon-128.png',
     title: opts.title,
@@ -56,8 +57,8 @@ function createUnlockRequestNotification (opts) {
 }
 
 function createTxNotification (state) {
-  // guard for chrome bug https://github.com/MetaMask/metamask-plugin/issues/236
-  if (!chrome.notifications) return console.error('Chrome notifications API missing...')
+  // guard for extension bug https://github.com/MetaMask/metamask-plugin/issues/236
+  if (!extension.notifications) return console.error('Chrome notifications API missing...')
 
   renderTxNotificationSVG(state, function (err, notificationSvgSource) {
     if (err) throw err
@@ -70,8 +71,8 @@ function createTxNotification (state) {
 }
 
 function createMsgNotification (state) {
-  // guard for chrome bug https://github.com/MetaMask/metamask-plugin/issues/236
-  if (!chrome.notifications) return console.error('Chrome notifications API missing...')
+  // guard for extension bug https://github.com/MetaMask/metamask-plugin/issues/236
+  if (!extension.notifications) return console.error('Chrome notifications API missing...')
 
   renderMsgNotificationSVG(state, function (err, notificationSvgSource) {
     if (err) throw err
@@ -84,11 +85,11 @@ function createMsgNotification (state) {
 }
 
 function showNotification (state) {
-  // guard for chrome bug https://github.com/MetaMask/metamask-plugin/issues/236
-  if (!chrome.notifications) return console.error('Chrome notifications API missing...')
+  // guard for extension bug https://github.com/MetaMask/metamask-plugin/issues/236
+  if (!extension.notifications) return console.error('Chrome notifications API missing...')
 
   var id = createId()
-  chrome.notifications.create(id, {
+  extension.notifications.create(id, {
     type: 'image',
     requireInteraction: true,
     iconUrl: '/images/icon-128.png',
diff --git a/app/scripts/metamask-controller.js b/app/scripts/metamask-controller.js
index 1b3b69932..7bf8fd5ea 100644
--- a/app/scripts/metamask-controller.js
+++ b/app/scripts/metamask-controller.js
@@ -6,6 +6,7 @@ const messageManager = require('./lib/message-manager')
 const HostStore = require('./lib/remote-store.js').HostStore
 const Web3 = require('web3')
 const ConfigManager = require('./lib/config-manager')
+const extension = require('./lib/extension')
 
 module.exports = class MetamaskController {
 
@@ -254,19 +255,19 @@ module.exports = class MetamaskController {
   // called from popup
   setRpcTarget (rpcTarget) {
     this.configManager.setRpcTarget(rpcTarget)
-    chrome.runtime.reload()
+    extension.runtime.reload()
     this.idStore.getNetwork()
   }
 
   setProviderType (type) {
     this.configManager.setProviderType(type)
-    chrome.runtime.reload()
+    extension.runtime.reload()
     this.idStore.getNetwork()
   }
 
   useEtherscanProvider () {
     this.configManager.useEtherscanProvider()
-    chrome.runtime.reload()
+    extension.runtime.reload()
   }
 }
 
diff --git a/app/scripts/popup.js b/app/scripts/popup.js
index 2e5b98896..20be15df7 100644
--- a/app/scripts/popup.js
+++ b/app/scripts/popup.js
@@ -9,6 +9,7 @@ const injectCss = require('inject-css')
 const PortStream = require('./lib/port-stream.js')
 const StreamProvider = require('web3-stream-provider')
 const setupMultiplex = require('./lib/stream-utils.js').setupMultiplex
+const extension = require('./lib/extension')
 
 // setup app
 var css = MetaMaskUiCss()
@@ -21,7 +22,7 @@ async.parallel({
 
 function connectToAccountManager (cb) {
   // setup communication with background
-  var pluginPort = chrome.runtime.connect({name: 'popup'})
+  var pluginPort = extension.runtime.connect({name: 'popup'})
   var portStream = new PortStream(pluginPort)
   // setup multiplexing
   var mx = setupMultiplex(portStream)
@@ -55,8 +56,8 @@ function setupControllerConnection (stream, cb) {
 
 function getCurrentDomain (cb) {
   const unknown = '<unknown>'
-  if (!chrome.tabs) return cb(null, unknown)
-  chrome.tabs.query({active: true, currentWindow: true}, function (results) {
+  if (!extension.tabs) return cb(null, unknown)
+  extension.tabs.query({active: true, currentWindow: true}, function (results) {
     var activeTab = results[0]
     var currentUrl = activeTab && activeTab.url
     var currentDomain = url.parse(currentUrl).host
@@ -68,9 +69,9 @@ function getCurrentDomain (cb) {
 }
 
 function clearNotifications(){
-  chrome.notifications.getAll(function (object) {
+  extension.notifications.getAll(function (object) {
     for (let notification in object){
-      chrome.notifications.clear(notification)
+      extension.notifications.clear(notification)
     }
   })
 }
diff --git a/docs/state_dump.md b/docs/state_dump.md
new file mode 100644
index 000000000..ecb863982
--- /dev/null
+++ b/docs/state_dump.md
@@ -0,0 +1,15 @@
+# How to take a State Dump
+
+Sometimes a UI bug is hard to reproduce, but we'd like to rapidly develop against the application state that caused the bug.
+
+In this case, a MetaMask developer will sometimes ask a user with a bug to perform a "state dump", so we can use some internal tools to reproduce and fix the bug.
+
+To take a state dump, follow these steps:
+
+1. Get the MetaMask popup to the point where it shows the bug (the developer will probably specify exactly where).
+2. Right click on the extension popup UI, and in the menu, click "Inspect". This will open the developer tools.
+3. In case it isn't already selected, click the "Console" tab in the new Developer Tools window.
+4. In the console, type this command exactly: `logState()`. This should print a bunch of JSON text into your console.
+5. Copy that printed JSON text
+6. *Optional*: Annonymize that text if you'd like (you may change all instances of an account address to another valid account address, for example) We may automate the anonymization in the future.
+7. Send that JSON text to the developer, ideally pasting it in the issue regarding the bug.
diff --git a/test/unit/extension-test.js b/test/unit/extension-test.js
new file mode 100644
index 000000000..0a03a3b97
--- /dev/null
+++ b/test/unit/extension-test.js
@@ -0,0 +1,39 @@
+var assert = require('assert')
+var sinon = require('sinon')
+const ethUtil = require('ethereumjs-util')
+
+var path = require('path')
+var Extension = require(path.join(__dirname, '..', '..', 'app', 'scripts', 'lib', 'extension-instance.js'))
+
+describe('extension', function() {
+
+  describe('with chrome global', function() {
+    let extension
+
+    beforeEach(function() {
+      window.chrome = {
+        alarms: 'foo'
+      }
+      extension = new Extension()
+    })
+
+    it('should use the chrome global apis', function() {
+      assert.equal(extension.alarms, 'foo')
+    })
+  })
+
+  describe('without chrome global', function() {
+    let extension
+
+    beforeEach(function() {
+      window.chrome = undefined
+      window.alarms = 'foo'
+      extension = new Extension()
+    })
+
+    it('should use the global apis', function() {
+      assert.equal(extension.alarms, 'foo')
+    })
+  })
+
+})
diff --git a/ui/app/components/transaction-list-item.js b/ui/app/components/transaction-list-item.js
index 78867fca4..796ba61ae 100644
--- a/ui/app/components/transaction-list-item.js
+++ b/ui/app/components/transaction-list-item.js
@@ -7,6 +7,7 @@ const addressSummary = require('../util').addressSummary
 const explorerLink = require('../../lib/explorer-link')
 const CopyButton = require('./copyButton')
 const vreme = new (require('vreme'))
+const extension = require('../../../app/scripts/lib/extension')
 
 const TransactionIcon = require('./transaction-list-item-icon')
 
@@ -49,7 +50,7 @@ TransactionListItem.prototype.render = function () {
 
         if (!transaction.hash || !isLinkable) return
         var url = explorerLink(transaction.hash, parseInt(network))
-        chrome.tabs.create({ url })
+        extension.tabs.create({ url })
       },
       style: {
         padding: '20px 0',
diff --git a/ui/app/info.js b/ui/app/info.js
index d97998fd7..4e540bd03 100644
--- a/ui/app/info.js
+++ b/ui/app/info.js
@@ -3,6 +3,7 @@ const Component = require('react').Component
 const h = require('react-hyperscript')
 const connect = require('react-redux').connect
 const actions = require('./actions')
+const extension = require('../../app/scripts/lib/extension')
 
 module.exports = connect(mapStateToProps)(InfoScreen)
 
@@ -19,7 +20,7 @@ InfoScreen.prototype.render = function () {
   var state = this.props
   var manifest
   try {
-    manifest = chrome.runtime.getManifest()
+    manifest = extension.runtime.getManifest()
   } catch (e) {
     manifest = { version: '2.0.0' }
   }
@@ -105,7 +106,7 @@ InfoScreen.prototype.render = function () {
                 h('a.info', {
                   target: '_blank',
                   style: { width: '85vw' },
-                  onClick () { chrome.tabs.create({url: 'mailto:help@metamask.io?subject=Feedback'}) },
+                  onClick () { extension.tabs.create({url: 'mailto:help@metamask.io?subject=Feedback'}) },
                 }, 'Email us any questions or comments!'),
               ]),
 
@@ -124,5 +125,5 @@ InfoScreen.prototype.render = function () {
 }
 
 InfoScreen.prototype.navigateTo = function (url) {
-  chrome.tabs.create({ url })
+  extension.tabs.create({ url })
 }