diff --git a/CliClient/app/services/plugins/PluginRunner.ts b/CliClient/app/services/plugins/PluginRunner.ts
index 1e06dc320..642914f09 100644
--- a/CliClient/app/services/plugins/PluginRunner.ts
+++ b/CliClient/app/services/plugins/PluginRunner.ts
@@ -54,15 +54,25 @@ export default class PluginRunner extends BasePluginRunner {
 		};
 	}
 
-	async run(plugin:Plugin, sandbox:Global) {
-		const vmSandbox = vm.createContext(this.newSandboxProxy(plugin.id, sandbox));
+	async run(plugin:Plugin, sandbox:Global):Promise<void> {
+		return new Promise((resolve:Function, reject:Function) => {
+			const onStarted = () => {
+				plugin.off('started', onStarted);
+				resolve();
+			};
 
-		try {
-			vm.runInContext(plugin.scriptText, vmSandbox);
-		} catch (error) {
-			this.logger().error(`In plugin ${plugin.id}:`, error);
-			return;
-		}
+			plugin.on('started', onStarted);
+
+			const vmSandbox = vm.createContext(this.newSandboxProxy(plugin.id, sandbox));
+
+			try {
+				vm.runInContext(plugin.scriptText, vmSandbox);
+			} catch (error) {
+				reject(error);
+				// this.logger().error(`In plugin ${plugin.id}:`, error);
+				// return;
+			}
+		});
 	}
 
 }
diff --git a/CliClient/tests/services_PluginService.ts b/CliClient/tests/services_PluginService.ts
index 64e00d9f9..afec92170 100644
--- a/CliClient/tests/services_PluginService.ts
+++ b/CliClient/tests/services_PluginService.ts
@@ -65,6 +65,9 @@ describe('services_PluginService', function() {
 
 		const allFolders = await Folder.all();
 		expect(allFolders.length).toBe(1);
+
+		// If you have an error here, it might mean you need to run `npm i` from
+		// the "withExternalModules" folder. Not clear exactly why.
 		expect(allFolders[0].title).toBe('  foo');
 	}));
 
diff --git a/ReactNativeClient/lib/services/plugins/BasePluginRunner.ts b/ReactNativeClient/lib/services/plugins/BasePluginRunner.ts
index 46d383db6..3af88eaab 100644
--- a/ReactNativeClient/lib/services/plugins/BasePluginRunner.ts
+++ b/ReactNativeClient/lib/services/plugins/BasePluginRunner.ts
@@ -4,7 +4,7 @@ import Global from './api/Global';
 
 export default abstract class BasePluginRunner extends BaseService {
 
-	async run(plugin:Plugin, sandbox:Global) {
+	async run(plugin:Plugin, sandbox:Global):Promise<void> {
 		throw new Error(`Not implemented: ${plugin} / ${sandbox}`);
 	}
 
diff --git a/ReactNativeClient/lib/services/plugins/Plugin.ts b/ReactNativeClient/lib/services/plugins/Plugin.ts
index 0f25e8c6d..f7cf32f67 100644
--- a/ReactNativeClient/lib/services/plugins/Plugin.ts
+++ b/ReactNativeClient/lib/services/plugins/Plugin.ts
@@ -4,6 +4,7 @@ import shim from 'lib/shim';
 import { ViewHandle } from './utils/createViewHandle';
 import { ContentScriptType } from './api/types';
 import Logger from 'lib/Logger';
+const EventEmitter = require('events');
 
 interface ViewControllers {
 	[key:string]: ViewController
@@ -29,6 +30,7 @@ export default class Plugin {
 	private viewControllers_:ViewControllers = {};
 	private contentScripts_:ContentScripts = {};
 	private dispatch_:Function;
+	private eventEmitter_:any;
 
 	constructor(id:string, baseDir:string, manifest:PluginManifest, scriptText:string, logger:Logger, dispatch:Function) {
 		this.id_ = id;
@@ -37,6 +39,7 @@ export default class Plugin {
 		this.scriptText_ = scriptText;
 		this.logger_ = logger;
 		this.dispatch_ = dispatch;
+		this.eventEmitter_ = new EventEmitter();
 	}
 
 	public get id():string {
@@ -59,11 +62,25 @@ export default class Plugin {
 		return this.baseDir_;
 	}
 
-	public registerContentScript(type:ContentScriptType, id:string, path:string) {
+	on(eventName:string, callback:Function) {
+		return this.eventEmitter_.on(eventName, callback);
+	}
+
+	off(eventName:string, callback:Function) {
+		return this.eventEmitter_.removeListener(eventName, callback);
+	}
+
+	emit(eventName:string, event:any = null) {
+		return this.eventEmitter_.emit(eventName, event);
+	}
+
+	public async registerContentScript(type:ContentScriptType, id:string, path:string) {
 		if (!this.contentScripts_[type]) this.contentScripts_[type] = [];
 
 		const absolutePath = shim.fsDriver().resolveRelativePathWithinDir(this.baseDir, path);
 
+		if (!(await shim.fsDriver().exists(absolutePath))) throw new Error(`Could not find content script at path ${absolutePath}`);
+
 		this.contentScripts_[type].push({ id, path: absolutePath });
 
 		this.logger_.debug(`Plugin: ${this.id}: Registered content script: ${type}: ${id}: ${absolutePath}`);
diff --git a/ReactNativeClient/lib/services/plugins/api/JoplinPlugins.ts b/ReactNativeClient/lib/services/plugins/api/JoplinPlugins.ts
index 06155d3d9..116fcdaf6 100644
--- a/ReactNativeClient/lib/services/plugins/api/JoplinPlugins.ts
+++ b/ReactNativeClient/lib/services/plugins/api/JoplinPlugins.ts
@@ -45,6 +45,7 @@ export default class JoplinPlugins {
 				this.logger.error(`In plugin ${this.plugin.id}:`, newError);
 			}).then(() => {
 				this.logger.info(`Finished running onStart handler: ${this.plugin.id} (Took ${Date.now() - startTime}ms)`);
+				this.plugin.emit('started');
 			});
 		}
 	}