diff --git a/cli/package.json b/cli/package.json
index ad9d1cbb0b9b..012ee33afe36 100644
--- a/cli/package.json
+++ b/cli/package.json
@@ -86,7 +86,7 @@
     "mocked-env": "1.2.4",
     "nock": "12.0.2",
     "postinstall-postinstall": "2.0.0",
-    "proxyquire": "2.1.0",
+    "proxyquire": "2.1.3",
     "resolve-pkg": "2.0.0",
     "shelljs": "0.8.3",
     "sinon": "7.2.2",
diff --git a/package.json b/package.json
index 6e5e31f4e819..47758b8d7adb 100644
--- a/package.json
+++ b/package.json
@@ -171,7 +171,7 @@
     "prefixed-list": "1.0.1",
     "pretty-ms": "6.0.1",
     "print-arch": "1.0.0",
-    "proxyquire": "2.1.0",
+    "proxyquire": "2.1.3",
     "ramda": "0.24.1",
     "shelljs": "0.8.3",
     "shx": "0.3.2",
diff --git a/packages/reporter/src/test/test.tsx b/packages/reporter/src/test/test.tsx
index a6555269f660..f3cf57690123 100644
--- a/packages/reporter/src/test/test.tsx
+++ b/packages/reporter/src/test/test.tsx
@@ -70,7 +70,10 @@ class Test extends Component<Props> {
 
     if (appState.autoScrollingEnabled && appState.isRunning && shouldRender && isActive != null) {
       window.requestAnimationFrame(() => {
-        scroller.scrollIntoView(this.containerRef.current as HTMLElement)
+        // since this executes async in a RAF the ref might be null
+        if (this.containerRef.current) {
+          scroller.scrollIntoView(this.containerRef.current as HTMLElement)
+        }
       })
     }
   }
diff --git a/packages/server/lib/browsers/firefox-util.ts b/packages/server/lib/browsers/firefox-util.ts
index 3c4078d264ac..41b329a90c69 100644
--- a/packages/server/lib/browsers/firefox-util.ts
+++ b/packages/server/lib/browsers/firefox-util.ts
@@ -177,6 +177,10 @@ export default {
 
     const { browser } = foxdriver
 
+    browser.on('error', (err) => {
+      debug('received error from foxdriver connection, ignoring %o', err)
+    })
+
     forceGcCc = () => {
       let gcDuration; let ccDuration
 
diff --git a/packages/server/lib/browsers/firefox.ts b/packages/server/lib/browsers/firefox.ts
index ff71136ba9de..97a3da67d053 100644
--- a/packages/server/lib/browsers/firefox.ts
+++ b/packages/server/lib/browsers/firefox.ts
@@ -9,7 +9,10 @@ import FirefoxProfile from 'firefox-profile'
 import firefoxUtil from './firefox-util'
 import utils from './utils'
 import * as launcherDebug from '@packages/launcher/lib/log'
-import { Browser } from './types'
+import { Browser, BrowserInstance } from './types'
+import { EventEmitter } from 'events'
+import os from 'os'
+import treeKill from 'tree-kill'
 const errors = require('../errors')
 
 const debug = Debug('cypress:server:browsers:firefox')
@@ -287,7 +290,23 @@ const defaultPreferences = {
   'marionette.log.level': launcherDebug.log.enabled ? 'Debug' : undefined,
 }
 
-export async function open (browser: Browser, url, options: any = {}) {
+export function _createDetachedInstance (browserInstance: BrowserInstance): BrowserInstance {
+  const detachedInstance: BrowserInstance = new EventEmitter() as BrowserInstance
+
+  detachedInstance.pid = browserInstance.pid
+
+  // kill the entire process tree, from the spawned instance up
+  detachedInstance.kill = (): void => {
+    treeKill(browserInstance.pid, (err?, result?) => {
+      debug('force-exit of process tree complete %o', { err, result })
+      detachedInstance.emit('exit')
+    })
+  }
+
+  return detachedInstance
+}
+
+export async function open (browser: Browser, url, options: any = {}): Bluebird<BrowserInstance> {
   const defaultLaunchOptions = utils.getDefaultLaunchOptions({
     extensions: [] as string[],
     preferences: _.extend({}, defaultPreferences),
@@ -347,7 +366,7 @@ export async function open (browser: Browser, url, options: any = {}) {
     launchOptions,
   ] = await Bluebird.all([
     utils.ensureCleanCache(browser, options.isTextTerminal),
-    utils.writeExtension(browser, options.isTextTerminal, options.proxyUrl, options.socketIoRoute, options.onScreencastFrame),
+    utils.writeExtension(browser, options.isTextTerminal, options.proxyUrl, options.socketIoRoute),
     utils.executeBeforeBrowserLaunch(browser, defaultLaunchOptions, options),
   ])
 
@@ -419,5 +438,11 @@ export async function open (browser: Browser, url, options: any = {}) {
     errors.throw('FIREFOX_COULD_NOT_CONNECT', err)
   })
 
+  if (os.platform() === 'win32') {
+    // override the .kill method for Windows so that the detached Firefox process closes between specs
+    // @see https://github.com/cypress-io/cypress/issues/6392
+    return _createDetachedInstance(browserInstance)
+  }
+
   return browserInstance
 }
diff --git a/packages/server/lib/browsers/types.ts b/packages/server/lib/browsers/types.ts
index 7b11010af87e..fdfdd6498cbd 100644
--- a/packages/server/lib/browsers/types.ts
+++ b/packages/server/lib/browsers/types.ts
@@ -1,7 +1,13 @@
 import { FoundBrowser } from '@packages/launcher'
+import { EventEmitter } from 'events'
 
 export type Browser = FoundBrowser & {
   majorVersion: number
   isHeadless: boolean
   isHeaded: boolean
 }
+
+export type BrowserInstance = EventEmitter & {
+  kill: () => void
+  pid: number
+}
diff --git a/packages/server/lib/browsers/utils.ts b/packages/server/lib/browsers/utils.ts
index 1870beeca509..09d0eedfd1df 100644
--- a/packages/server/lib/browsers/utils.ts
+++ b/packages/server/lib/browsers/utils.ts
@@ -205,12 +205,12 @@ export = {
 
   launch: launcher.launch,
 
-  writeExtension (browser, isTextTerminal, proxyUrl, socketIoRoute, onScreencastFrame) {
+  writeExtension (browser, isTextTerminal, proxyUrl, socketIoRoute) {
     debug('writing extension')
 
     // debug('writing extension to chrome browser')
     // get the string bytes for the final extension file
-    return extension.setHostAndPath(proxyUrl, socketIoRoute, onScreencastFrame)
+    return extension.setHostAndPath(proxyUrl, socketIoRoute)
     .then((str) => {
       const extensionDest = getExtensionDir(browser, isTextTerminal)
       const extensionBg = path.join(extensionDest, 'background.js')
@@ -231,7 +231,7 @@ export = {
     debug('getBrowsers')
 
     return launcher.detect()
-    .then((browsers = []) => {
+    .then((browsers: FoundBrowser[] = []) => {
       let majorVersion
 
       debug('found browsers %o', { browsers })
diff --git a/packages/server/package.json b/packages/server/package.json
index c5973f1a15b7..9365a2fb01e7 100644
--- a/packages/server/package.json
+++ b/packages/server/package.json
@@ -96,7 +96,7 @@
     "pluralize": "8.0.0",
     "ramda": "0.24.1",
     "randomstring": "1.1.5",
-    "resolve": "1.13.1",
+    "resolve": "1.17.0",
     "return-deep-diff": "0.4.0",
     "sanitize-filename": "1.6.3",
     "semver": "6.3.0",
@@ -110,11 +110,12 @@
     "term-size": "2.1.0",
     "tough-cookie": "4.0.0",
     "trash": "5.2.0",
+    "tree-kill": "1.2.2",
     "ts-node": "8.5.4",
     "underscore": "1.9.1",
     "underscore.string": "3.3.5",
     "url-parse": "1.4.7",
-    "uuid": "3.3.2",
+    "uuid": "3.4.0",
     "which": "2.0.2",
     "widest-line": "3.1.0",
     "winston": "2.4.4"
@@ -174,7 +175,7 @@
     "mockery": "2.1.0",
     "multiparty": "4.2.1",
     "nock": "12.0.2",
-    "proxyquire": "2.1.0",
+    "proxyquire": "2.1.3",
     "react": "16.8.6",
     "repl.history": "0.1.4",
     "sinon": "5.1.1",
diff --git a/packages/server/test/e2e/1_firefox_spec.ts b/packages/server/test/e2e/1_firefox_spec.ts
index 74d8a8f41227..9f42624ce604 100644
--- a/packages/server/test/e2e/1_firefox_spec.ts
+++ b/packages/server/test/e2e/1_firefox_spec.ts
@@ -68,4 +68,12 @@ describe('e2e firefox', function () {
       expect(stderr).not.to.include('foxdriver')
     },
   })
+
+  // NOTE: only an issue on windows
+  // https://github.com/cypress-io/cypress/issues/6392
+  e2e.it.skip('can run multiple specs', {
+    browser: 'firefox',
+    project: Fixtures.projectPath('e2e'),
+    spec: 'simple_spec.coffee,simple_passing_spec.coffee',
+  })
 })
diff --git a/packages/server/test/unit/browsers/firefox_spec.ts b/packages/server/test/unit/browsers/firefox_spec.ts
index 6ee69a500218..f2d737cbf479 100644
--- a/packages/server/test/unit/browsers/firefox_spec.ts
+++ b/packages/server/test/unit/browsers/firefox_spec.ts
@@ -8,6 +8,7 @@ import * as firefox from '../../../lib/browsers/firefox'
 import { EventEmitter } from 'events'
 import Marionette from 'marionette-client'
 import Foxdriver from '@benmalka/foxdriver'
+import os from 'os'
 const mockfs = require('mock-fs')
 const FirefoxProfile = require('firefox-profile')
 const utils = require('../../../lib/browsers/utils')
@@ -67,6 +68,7 @@ describe('lib/browsers/firefox', () => {
     const browser = {
       listTabs: sinon.stub().resolves([foxdriverTab]),
       request: sinon.stub().withArgs('listTabs').resolves({ tabs: [foxdriverTab] }),
+      on: sinon.stub(),
     }
 
     foxdriver = {
@@ -102,6 +104,11 @@ describe('lib/browsers/firefox', () => {
         browser: this.browser,
       }
 
+      this.browserInstance = {
+        // should be high enough to not kill any real PIDs
+        pid: Number.MAX_SAFE_INTEGER,
+      }
+
       sinon.stub(process, 'pid').value(1111)
 
       protocol.foo = 'bar'
@@ -109,7 +116,6 @@ describe('lib/browsers/firefox', () => {
       sinon.stub(plugins, 'has')
       sinon.stub(plugins, 'execute')
       sinon.stub(utils, 'writeExtension').resolves('/path/to/ext')
-      this.browserInstance = {}
       sinon.stub(utils, 'launch').resolves(this.browserInstance)
       sinon.spy(FirefoxProfile.prototype, 'setPreference')
       sinon.spy(FirefoxProfile.prototype, 'updatePreferences')
@@ -201,7 +207,7 @@ describe('lib/browsers/firefox', () => {
 
     it('writes extension', function () {
       return firefox.open(this.browser, 'http://', this.options).then(() => {
-        expect(utils.writeExtension).to.be.calledWith(this.options.browser, this.options.isTextTerminal, this.options.proxyUrl, this.options.socketIoRoute, this.options.onScreencastFrame)
+        expect(utils.writeExtension).to.be.calledWith(this.options.browser, this.options.isTextTerminal, this.options.proxyUrl, this.options.socketIoRoute)
       })
     })
 
@@ -322,6 +328,29 @@ describe('lib/browsers/firefox', () => {
         expect(wrapperErr.message).to.include(err.message)
       })
     })
+
+    context('returns BrowserInstance', function () {
+      it('from browsers.launch', async function () {
+        const instance = await firefox.open(this.browser, 'http://', this.options)
+
+        expect(instance).to.eq(this.browserInstance)
+      })
+
+      // @see https://github.com/cypress-io/cypress/issues/6392
+      it('detached on Windows', async function () {
+        sinon.stub(os, 'platform').returns('win32')
+        const instance = await firefox.open(this.browser, 'http://', this.options)
+
+        expect(instance).to.not.eq(this.browserInstance)
+        expect(instance.pid).to.eq(this.browserInstance.pid)
+
+        await new Promise((resolve) => {
+          // ensure events are wired as expected
+          instance.on('exit', resolve)
+          instance.kill()
+        })
+      })
+    })
   })
 
   context('firefox-util', () => {
diff --git a/yarn.lock b/yarn.lock
index 8b6d105e67da..182b39619bcc 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -13931,16 +13931,7 @@ http-proxy-agent@^2.1.0:
     agent-base "4"
     debug "3.1.0"
 
-http-proxy@^1.17.0:
-  version "1.18.1"
-  resolved "https://registry.yarnpkg.com/http-proxy/-/http-proxy-1.18.1.tgz#401541f0534884bbf95260334e72f88ee3976549"
-  integrity sha512-7mz/721AbnJwIVbnaSv1Cz3Am0ZLT/UBwkC92VlxhXv/k/BBQfM2fXElQNC27BVGr0uwUpplYPQM9LnaBMR5NQ==
-  dependencies:
-    eventemitter3 "^4.0.0"
-    follow-redirects "^1.0.0"
-    requires-port "^1.0.0"
-
-http-proxy@cypress-io/node-http-proxy#9322b4b69b34f13a6f3874e660a35df3305179c6:
+http-proxy@^1.17.0, http-proxy@cypress-io/node-http-proxy#9322b4b69b34f13a6f3874e660a35df3305179c6:
   version "1.18.0"
   resolved "https://codeload.github.com/cypress-io/node-http-proxy/tar.gz/9322b4b69b34f13a6f3874e660a35df3305179c6"
   dependencies:
@@ -18078,7 +18069,7 @@ module-lookup-amd@^6.1.0:
     requirejs "^2.3.5"
     requirejs-config-file "^3.1.1"
 
-module-not-found-error@^1.0.0:
+module-not-found-error@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/module-not-found-error/-/module-not-found-error-1.0.1.tgz#cf8b4ff4f29640674d6cdd02b0e3bc523c2bbdc0"
   integrity sha1-z4tP9PKWQGdNbN0CsOO8UjwrvcA=
@@ -19728,7 +19719,7 @@ path-key@^3.0.0, path-key@^3.1.0:
   resolved "https://registry.yarnpkg.com/path-key/-/path-key-3.1.1.tgz#581f6ade658cbba65a0d3380de7753295054f375"
   integrity sha512-ojmeN0qd+y0jszEtoY48r0Peq5dwMEkIlCOu6Q5f41lfkswXuKtYrhgoTpLnyIcHm24Uhqx+5Tqm2InSwLhE6Q==
 
-path-parse@^1.0.5, path-parse@^1.0.6:
+path-parse@^1.0.6:
   version "1.0.6"
   resolved "https://registry.yarnpkg.com/path-parse/-/path-parse-1.0.6.tgz#d62dbb5679405d72c4737ec58600e9ddcf06d24c"
   integrity sha512-GSmOT2EbHrINBf9SR7CDELwlJ8AENk3Qn7OikK4nFYAu3Ote2+JYNVvkpAEQm3/TLNEJFD/xZJjzyxg3KBWOzw==
@@ -20429,14 +20420,14 @@ proxy-from-env@1.1.0, proxy-from-env@^1.0.0:
   resolved "https://registry.yarnpkg.com/proxy-from-env/-/proxy-from-env-1.1.0.tgz#e102f16ca355424865755d2c9e8ea4f24d58c3e2"
   integrity sha512-D+zkORCbA9f1tdWRK0RaCR3GPv50cMxcrz4X8k5LTSUD1Dkw47mKJEZQNunItRTkWwgtaUSo1RVFRIG9ZXiFYg==
 
-proxyquire@2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/proxyquire/-/proxyquire-2.1.0.tgz#c2263a38bf0725f2ae950facc130e27510edce8d"
-  integrity sha512-kptdFArCfGRtQFv3Qwjr10lwbEV0TBJYvfqzhwucyfEXqVgmnAkyEw/S3FYzR5HI9i5QOq4rcqQjZ6AlknlCDQ==
+proxyquire@2.1.3:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/proxyquire/-/proxyquire-2.1.3.tgz#2049a7eefa10a9a953346a18e54aab2b4268df39"
+  integrity sha512-BQWfCqYM+QINd+yawJz23tbBM40VIGXOdDw3X344KcclI/gtBbdWF6SlQ4nK/bYhF9d27KYug9WzljHC6B9Ysg==
   dependencies:
     fill-keys "^1.0.2"
-    module-not-found-error "^1.0.0"
-    resolve "~1.8.1"
+    module-not-found-error "^1.0.1"
+    resolve "^1.11.1"
 
 prr@~1.0.1:
   version "1.0.1"
@@ -21890,10 +21881,10 @@ resolve@1.1.7, resolve@1.1.x:
   resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.1.7.tgz#203114d82ad2c5ed9e8e0411b3932875e889e97b"
   integrity sha1-IDEU2CrSxe2ejgQRs5ModeiJ6Xs=
 
-resolve@1.13.1:
-  version "1.13.1"
-  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.13.1.tgz#be0aa4c06acd53083505abb35f4d66932ab35d16"
-  integrity sha512-CxqObCX8K8YtAhOBRg+lrcdn+LK+WYOS8tSjqSFbjtrI5PnS63QPhZl4+yKfrU9tdsbMu9Anr/amegT87M9Z6w==
+resolve@1.17.0, resolve@^1.1.4, resolve@^1.1.6, resolve@^1.1.7, resolve@^1.10.0, resolve@^1.11.1, resolve@^1.12.0, resolve@^1.14.2, resolve@^1.3.2, resolve@^1.4.0, resolve@^1.8.1:
+  version "1.17.0"
+  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.17.0.tgz#b25941b54968231cc2d1bb76a79cb7f2c0bf8444"
+  integrity sha512-ic+7JYiV8Vi2yzQGFWOkiZD5Z9z7O2Zhm9XMaTxdJExKasieFCr+yXZ/WmXsckHiKl12ar0y6XiXDx3m4RHn1w==
   dependencies:
     path-parse "^1.0.6"
 
@@ -21902,20 +21893,6 @@ resolve@^0.6.3:
   resolved "https://registry.yarnpkg.com/resolve/-/resolve-0.6.3.tgz#dd957982e7e736debdf53b58a4dd91754575dd46"
   integrity sha1-3ZV5gufnNt699TtYpN2RdUV13UY=
 
-resolve@^1.1.4, resolve@^1.1.6, resolve@^1.1.7, resolve@^1.10.0, resolve@^1.11.1, resolve@^1.12.0, resolve@^1.14.2, resolve@^1.3.2, resolve@^1.4.0, resolve@^1.8.1:
-  version "1.17.0"
-  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.17.0.tgz#b25941b54968231cc2d1bb76a79cb7f2c0bf8444"
-  integrity sha512-ic+7JYiV8Vi2yzQGFWOkiZD5Z9z7O2Zhm9XMaTxdJExKasieFCr+yXZ/WmXsckHiKl12ar0y6XiXDx3m4RHn1w==
-  dependencies:
-    path-parse "^1.0.6"
-
-resolve@~1.8.1:
-  version "1.8.1"
-  resolved "https://registry.yarnpkg.com/resolve/-/resolve-1.8.1.tgz#82f1ec19a423ac1fbd080b0bab06ba36e84a7a26"
-  integrity sha512-AicPrAC7Qu1JxPCZ9ZgCZlY35QgFnNqc+0LtbRNxnVw4TXvjQ72wnuL9JQcEBgXkI9JM8MsT9kaQoHcpCRJOYA==
-  dependencies:
-    path-parse "^1.0.5"
-
 responselike@1.0.2, responselike@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/responselike/-/responselike-1.0.2.tgz#918720ef3b631c5642be068f15ade5a46f4ba1e7"
@@ -24447,7 +24424,7 @@ traverse-chain@~0.1.0:
   resolved "https://registry.yarnpkg.com/traverse-chain/-/traverse-chain-0.1.0.tgz#61dbc2d53b69ff6091a12a168fd7d433107e40f1"
   integrity sha1-YdvC1Ttp/2CRoSoWj9fUMxB+QPE=
 
-tree-kill@^1.1.0:
+tree-kill@1.2.2, tree-kill@^1.1.0:
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/tree-kill/-/tree-kill-1.2.2.tgz#4ca09a9092c88b73a7cdc5e8a01b507b0790a0cc"
   integrity sha512-L0Orpi8qGpRG//Nd+H90vFB+3iHnue1zSSGmNOOCh1GLJ7rUKVwV2HvijphGQS2UmhUZewS9VgvxYIdgr+fG1A==
@@ -25269,7 +25246,7 @@ uuid@3.3.2:
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.3.2.tgz#1b4af4955eb3077c501c23872fc6513811587131"
   integrity sha512-yXJmeNaw3DnnKAOKJE51sL/ZaYfWJRl1pK9dr19YFCu0ObS231AB1/LbqTKRAQ5kw8A90rA6fr4riOUpTZvQZA==
 
-uuid@^3.0.0, uuid@^3.0.1, uuid@^3.1.0, uuid@^3.3.2, uuid@^3.3.3:
+uuid@3.4.0, uuid@^3.0.0, uuid@^3.0.1, uuid@^3.1.0, uuid@^3.3.2, uuid@^3.3.3:
   version "3.4.0"
   resolved "https://registry.yarnpkg.com/uuid/-/uuid-3.4.0.tgz#b23e4358afa8a202fe7a100af1f5f883f02007ee"
   integrity sha512-HjSDRw6gZE5JMggctHBcjVak08+KEVhSIiDzFnT9S9aegmp85S/bReBVTb4QTFaRNptJ9kuYaNhnbNEOkbKb/A==