diff --git a/packages/desktop-gui/src/styles/components/_alerts.scss b/packages/desktop-gui/src/styles/components/_alerts.scss
index 27832af46d..5b7f75ae5f 100644
--- a/packages/desktop-gui/src/styles/components/_alerts.scss
+++ b/packages/desktop-gui/src/styles/components/_alerts.scss
@@ -56,6 +56,10 @@
 
   .alert-content {
     text-align: left;
+
+    p {
+      line-height: 1.5;
+    }
   }
 
   code, pre {
diff --git a/packages/server/__snapshots__/3_plugins_spec.js b/packages/server/__snapshots__/3_plugins_spec.js
index 03e4a60844..41b2bf1aaa 100644
--- a/packages/server/__snapshots__/3_plugins_spec.js
+++ b/packages/server/__snapshots__/3_plugins_spec.js
@@ -461,3 +461,21 @@ The following error was thrown by a plugin. We stopped running your tests becaus
 
 
 `
+
+exports['e2e plugins projectRoot and configFile passes projectRoot and default configFile to plugins function 1'] = `
+The following validation error was thrown by your plugins file (\`/foo/bar/.projects/plugin-validation-error/cypress/plugins/index.js\`).
+
+ Error: You must pass a valid event name when registering a plugin.
+
+You passed: \`invalid:event\`
+
+The following are valid events:
+- file:preprocessor
+- before:browser:launch
+- task
+- after:screenshot
+
+    [stack trace lines]
+
+
+`
diff --git a/packages/server/lib/errors.coffee b/packages/server/lib/errors.coffee
index fb54062aac..d5f22cb086 100644
--- a/packages/server/lib/errors.coffee
+++ b/packages/server/lib/errors.coffee
@@ -592,6 +592,11 @@ getMsgByType = (type, arg1 = {}, arg2, arg3) ->
       The following error was thrown by a plugin. We stopped running your tests because a plugin crashed. Please check your plugins file (`#{arg1}`)
       """.trim()
       return {msg: msg, details: arg2}
+    when "PLUGINS_VALIDATION_ERROR"
+      msg = """
+      The following validation error was thrown by your plugins file (`#{arg1}`).
+      """.trim()
+      return {msg: msg, details: arg2}
     when "BUNDLE_ERROR"
       ## IF YOU MODIFY THIS MAKE SURE TO UPDATE
       ## THE ERROR MESSAGE IN THE RUNNER TOO
diff --git a/packages/server/lib/plugins/child/run_plugins.js b/packages/server/lib/plugins/child/run_plugins.js
index e3e3fcb020..e859d5ab02 100644
--- a/packages/server/lib/plugins/child/run_plugins.js
+++ b/packages/server/lib/plugins/child/run_plugins.js
@@ -4,10 +4,12 @@
 const _ = require('lodash')
 const debug = require('debug')('cypress:server:plugins:child')
 const Promise = require('bluebird')
+
+const errors = require('../../errors')
 const preprocessor = require('./preprocessor')
 const task = require('./task')
 const util = require('../util')
-const errors = require('../../errors')
+const validateEvent = require('./validate_event')
 
 const ARRAY_METHODS = ['concat', 'push', 'unshift', 'slice', 'pop', 'shift', 'slice', 'splice', 'filter', 'map', 'forEach', 'reduce', 'reverse', 'splice', 'includes']
 
@@ -16,23 +18,9 @@ const registeredEvents = {}
 const invoke = (eventId, args = []) => {
   const event = registeredEvents[eventId]
 
-  if (!event) {
-    sendError(new Error(`No handler registered for event id ${eventId}`))
-
-    return
-  }
-
   return event.handler(...args)
 }
 
-const sendError = (ipc, err) => {
-  ipc.send('error', util.serializeError(err))
-}
-
-const sendWarning = (ipc, warningErr) => {
-  ipc.send('warning', util.serializeError(warningErr))
-}
-
 let plugins
 
 const load = (ipc, config, pluginsFile) => {
@@ -44,6 +32,14 @@ const load = (ipc, config, pluginsFile) => {
   // we track the register calls and then send them all at once
   // to the parent process
   const register = (event, handler) => {
+    const { isValid, error } = validateEvent(event, handler)
+
+    if (!isValid) {
+      ipc.send('load:error', 'PLUGINS_VALIDATION_ERROR', pluginsFile, error.stack)
+
+      return
+    }
+
     if (event === 'task') {
       const existingEventId = _.findKey(registeredEvents, { event: 'task' })
 
@@ -74,12 +70,16 @@ const load = (ipc, config, pluginsFile) => {
 
   Promise
   .try(() => {
+    debug('run plugins function')
+
     return plugins(register, config)
   })
   .then((modifiedCfg) => {
+    debug('plugins file successfully loaded')
     ipc.send('loaded', modifiedCfg, registrations)
   })
   .catch((err) => {
+    debug('plugins file errored:', err && err.stack)
     ipc.send('load:error', 'PLUGINS_FUNCTION_ERROR', pluginsFile, err.stack)
   })
 }
@@ -113,10 +113,9 @@ const execute = (ipc, event, ids, args = []) => {
 
           hasEmittedWarning = true
 
-          sendWarning(ipc,
-            errors.get(
-              'DEPRECATED_BEFORE_BROWSER_LAUNCH_ARGS',
-            ))
+          const warning = errors.get('DEPRECATED_BEFORE_BROWSER_LAUNCH_ARGS')
+
+          ipc.send('warning', util.serializeError(warning))
 
           // eslint-disable-next-line prefer-rest-params
           return boundFn.apply(this, arguments)
diff --git a/packages/server/lib/plugins/child/validate_event.js b/packages/server/lib/plugins/child/validate_event.js
new file mode 100644
index 0000000000..4ad4caf075
--- /dev/null
+++ b/packages/server/lib/plugins/child/validate_event.js
@@ -0,0 +1,45 @@
+const _ = require('lodash')
+
+const createErrorResult = (errorMessage) => ({ isValid: false, error: new Error(errorMessage) })
+const createSuccessResult = () => ({ isValid: true })
+
+const validate = (func, arg, errorMessage) => {
+  return func(arg) ? createSuccessResult() : createErrorResult(errorMessage)
+}
+
+const isFunction = (event, handler) => {
+  return validate(_.isFunction, handler, `The handler for the event \`${event}\` must be a function`)
+}
+
+const isObject = (event, handler) => {
+  return validate(_.isPlainObject, handler, `The handler for the event \`${event}\` must be an object`)
+}
+
+const eventValidators = {
+  'file:preprocessor': isFunction,
+  'before:browser:launch': isFunction,
+  'task': isObject,
+  'after:screenshot': isFunction,
+  '_get:task:keys': isFunction,
+  '_get:task:body': isFunction,
+}
+
+const validateEvent = (event, handler) => {
+  const validator = eventValidators[event]
+
+  if (!validator) {
+    const userEvents = _.reject(_.keys(eventValidators), (event) => event.startsWith('_'))
+
+    return createErrorResult(`You must pass a valid event name when registering a plugin.
+
+You passed: \`${event}\`
+
+The following are valid events:
+- ${userEvents.join('\n- ')}
+`)
+  }
+
+  return validator(event, handler)
+}
+
+module.exports = validateEvent
diff --git a/packages/server/lib/server.coffee b/packages/server/lib/server.coffee
index 4e859fee39..338a5c0c01 100644
--- a/packages/server/lib/server.coffee
+++ b/packages/server/lib/server.coffee
@@ -164,6 +164,7 @@ class Server
 
   open: (config = {}, project, onError, onWarning) ->
     debug("server open")
+
     la(_.isPlainObject(config), "expected plain config object", config)
 
     Promise.try =>
diff --git a/packages/server/test/e2e/3_plugins_spec.js b/packages/server/test/e2e/3_plugins_spec.js
index 727813810e..9628c92e0e 100644
--- a/packages/server/test/e2e/3_plugins_spec.js
+++ b/packages/server/test/e2e/3_plugins_spec.js
@@ -15,6 +15,7 @@ const pluginAfterScreenshot = Fixtures.projectPath('plugin-after-screenshot')
 const pluginReturnsBadConfig = Fixtures.projectPath('plugin-returns-bad-config')
 const pluginReturnsEmptyBrowsersList = Fixtures.projectPath('plugin-returns-empty-browsers-list')
 const pluginReturnsInvalidBrowser = Fixtures.projectPath('plugin-returns-invalid-browser')
+const pluginValidationError = Fixtures.projectPath('plugin-validation-error')
 
 describe('e2e plugins', function () {
   e2e.setup()
@@ -134,6 +135,16 @@ describe('e2e plugins', function () {
     })
   })
 
+  it('fails when invalid event is registered', function () {
+    e2e.exec(this, {
+      spec: 'app_spec.js',
+      project: pluginValidationError,
+      sanitizeScreenshotDimensions: true,
+      snapshot: true,
+      expectedExitCode: 1,
+    })
+  })
+
   describe('projectRoot and configFile', function () {
     it('passes projectRoot and default configFile to plugins function', function () {
       return e2e.exec(this, {
diff --git a/packages/server/test/support/fixtures/projects/plugin-before-browser-launch-deprecation/cypress/plugins/index.js b/packages/server/test/support/fixtures/projects/plugin-before-browser-launch-deprecation/cypress/plugins/index.js
index 96ea549772..a52576c6c3 100644
--- a/packages/server/test/support/fixtures/projects/plugin-before-browser-launch-deprecation/cypress/plugins/index.js
+++ b/packages/server/test/support/fixtures/projects/plugin-before-browser-launch-deprecation/cypress/plugins/index.js
@@ -44,7 +44,6 @@ const getHandlersByType = (type) => {
           return launchOptions
         },
         onTask: { assertPsOutput: assertPsOutput('--foo') },
-
       }
 
     case 'return-launch-options-mutate-only-args-property':
@@ -57,7 +56,6 @@ const getHandlersByType = (type) => {
           return launchOptions
         },
         onTask: { assertPsOutput: assertPsOutput(['--foo', '--bar']) },
-
       }
 
     case 'return-undefined-mutate-array':
@@ -70,7 +68,6 @@ const getHandlersByType = (type) => {
           return
         },
         onTask: { assertPsOutput: assertPsOutput([]) },
-
       }
 
     case 'return-unknown-properties':
@@ -83,6 +80,7 @@ const getHandlersByType = (type) => {
 
           return launchOptions
         },
+        onTask: {},
       }
 
     case 'throw-explicit-error':
@@ -90,6 +88,7 @@ const getHandlersByType = (type) => {
         onBeforeBrowserLaunch (browser, launchOptions) {
           throw new Error('Error thrown from plugins handler')
         },
+        onTask: {},
       }
 
     case 'reject-promise':
@@ -101,6 +100,7 @@ const getHandlersByType = (type) => {
             throw new Error('Promise rejected from plugins handler')
           })
         },
+        onTask: {},
       }
 
     default: () => {
diff --git a/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress.json b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress.json
new file mode 100644
index 0000000000..0967ef424b
--- /dev/null
+++ b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress.json
@@ -0,0 +1 @@
+{}
diff --git a/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/integration/app_spec.js b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/integration/app_spec.js
new file mode 100644
index 0000000000..99a13400ed
--- /dev/null
+++ b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/integration/app_spec.js
@@ -0,0 +1,3 @@
+it('passes', () => {
+  expect(true).to.be.true
+})
diff --git a/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/plugins/index.js b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/plugins/index.js
new file mode 100644
index 0000000000..5777196b75
--- /dev/null
+++ b/packages/server/test/support/fixtures/projects/plugin-validation-error/cypress/plugins/index.js
@@ -0,0 +1,3 @@
+module.exports = (on) => {
+  on('invalid:event', () => {})
+}
diff --git a/packages/server/test/unit/plugins/child/validate_event_spec.js b/packages/server/test/unit/plugins/child/validate_event_spec.js
new file mode 100644
index 0000000000..86d7e7142e
--- /dev/null
+++ b/packages/server/test/unit/plugins/child/validate_event_spec.js
@@ -0,0 +1,69 @@
+require('../../../spec_helper')
+
+const _ = require('lodash')
+const validateEvent = require('../../../../lib/plugins/child/validate_event')
+
+const events = [
+  ['file:preprocessor', 'a function', () => {}],
+  ['before:browser:launch', 'a function', () => {}],
+  ['after:screenshot', 'a function', () => {}],
+  ['task', 'an object', {}],
+]
+
+describe('lib/plugins/child/validate_event', () => {
+  it('returns error when called with no event name', () => {
+    const { isValid, error } = validateEvent()
+
+    expect(isValid).to.be.false
+    expect(error.message).to.equal(`You must pass a valid event name when registering a plugin.
+
+You passed: \`undefined\`
+
+The following are valid events:
+- file:preprocessor
+- before:browser:launch
+- task
+- after:screenshot
+`)
+  })
+
+  it('returns error when called with no event handler', () => {
+    const { isValid, error } = validateEvent('file:preprocessor')
+
+    expect(isValid).to.be.false
+    expect(error.message).to.equal('The handler for the event `file:preprocessor` must be a function')
+  })
+
+  it('returns error when called with unsupported event name', () => {
+    const { isValid, error } = validateEvent('invalid:event:name', {})
+
+    expect(isValid).to.be.false
+    expect(error.message).to.equal(`You must pass a valid event name when registering a plugin.
+
+You passed: \`invalid:event:name\`
+
+The following are valid events:
+- file:preprocessor
+- before:browser:launch
+- task
+- after:screenshot
+`)
+  })
+
+  _.each(events, ([event, type]) => {
+    it(`returns error when event handler of ${event} is not ${type}`, () => {
+      const { isValid, error } = validateEvent(event, 'invalid type')
+
+      expect(isValid).to.be.false
+      expect(error.message).to.equal(`The handler for the event \`${event}\` must be ${type}`)
+    })
+  })
+
+  _.each(events, ([event, type, validValue]) => {
+    it(`returns success when event handler of ${event} is ${type}`, () => {
+      const { isValid } = validateEvent(event, validValue)
+
+      expect(isValid).to.be.true
+    })
+  })
+})