diff --git a/js/misc/errorUtils.js b/js/misc/errorUtils.js
index c2bc1c794..369a06b02 100644
--- a/js/misc/errorUtils.js
+++ b/js/misc/errorUtils.js
@@ -14,8 +14,8 @@ function formatExceptionStack(error) {
     return `\n\nStack trace:\n${indentedStack}`;
 }
 
-function formatExceptionWithCause(error, seenCauses) {
-    let fmt = formatExceptionStack(error);
+function formatExceptionWithCause(error, seenCauses, showStack) {
+    let fmt = showStack ? formatExceptionStack(error) : '';
 
     const {cause} = error;
     if (!cause)
@@ -39,9 +39,12 @@ function formatExceptionWithCause(error, seenCauses) {
  * location where a SyntaxError was thrown into account.
  *
  * @param {Error} error The error to format
+ * @param {object} options Formatting options
+ * @param {boolean} options.showStack Whether to show the stack trace (default
+ *   true)
  * @returns {string} The formatted string
  */
-export function formatError(error) {
+export function formatError(error, {showStack = true} = {}) {
     try {
         let fmt = `${error}`;
         if (error === null || typeof error !== 'object')
@@ -49,12 +52,13 @@ export function formatError(error) {
 
         if (error instanceof SyntaxError) {
             fmt += formatSyntaxErrorLocation(error);
-            fmt += formatExceptionStack(error);
+            if (showStack)
+                fmt += formatExceptionStack(error);
             return fmt;
         }
 
         const seenCauses = new Set([error]);
-        fmt += formatExceptionWithCause(error, seenCauses);
+        fmt += formatExceptionWithCause(error, seenCauses, showStack);
         return fmt;
     } catch (e) {
         return `(could not display error: ${e})`;
diff --git a/js/ui/extensionSystem.js b/js/ui/extensionSystem.js
index 0ff282809..ddadb384e 100644
--- a/js/ui/extensionSystem.js
+++ b/js/ui/extensionSystem.js
@@ -9,6 +9,7 @@ import * as Signals from '../misc/signals.js';
 
 import * as Config from '../misc/config.js';
 import * as ExtensionDownloader from './extensionDownloader.js';
+import {formatError} from '../misc/errorUtils.js';
 import {ExtensionState, ExtensionType} from '../misc/extensionUtils.js';
 import * as FileUtils from '../misc/fileUtils.js';
 import * as Main from './main.js';
@@ -359,8 +360,7 @@ export class ExtensionManager extends Signals.EventEmitter {
         if (!extension)
             return;
 
-        const message = error instanceof Error
-            ? error.message : error.toString();
+        const message = formatError(error, {showStack: false});
 
         console.debug(`Changing state of extension ${uuid} to ERROR`);
         extension.error = message;