diff --git a/app/javascript/controllers/autosave_controller.ts b/app/javascript/controllers/autosave_controller.ts
index 824f354d5..547321fca 100644
--- a/app/javascript/controllers/autosave_controller.ts
+++ b/app/javascript/controllers/autosave_controller.ts
@@ -4,6 +4,11 @@ import { z } from 'zod';
 
 import { ApplicationController } from './application_controller';
 import { AutoUpload } from '../shared/activestorage/auto-upload';
+import {
+  FileUploadError,
+  FAILURE_CLIENT,
+  ERROR_CODE_READ
+} from '../shared/activestorage/file-upload-error';
 
 const Gon = z.object({ autosave: z.object({ debounce_delay: z.number() }) });
 
@@ -95,7 +100,19 @@ export class AutosaveController extends ApplicationController {
 
   private enqueueAutouploadRequest(target: HTMLInputElement, file: File) {
     const autoupload = new AutoUpload(target, file);
-    autoupload.start();
+    try {
+      autoupload.start();
+    } catch (e) {
+      const error = e as FileUploadError;
+      // Report unexpected client errors to Sentry.
+      // (But ignore usual client errors, or errors we can monitor better on the server side.)
+      if (
+        error.failureReason == FAILURE_CLIENT &&
+        error.code != ERROR_CODE_READ
+      ) {
+        throw error;
+      }
+    }
   }
 
   // Add a new autosave request to the queue.