diff -r 81fc811c3c39 toolkit/components/translations/actors/TranslationsParent.sys.mjs
--- a/toolkit/components/translations/actors/TranslationsParent.sys.mjs Thu Aug 08 21:26:29 2024 -0700
+++ b/toolkit/components/translations/actors/TranslationsParent.sys.mjs Sat Aug 10 16:45:13 2024 -0700
@@ -618,16 +618,25 @@
    * Detect if Wasm SIMD is supported, and cache the value. It's better to check
    * for support before downloading large binary blobs to a user who can't even
    * use the feature. This function also respects mocks and simulating unsupported
    * engines.
    *
    * @type {boolean}
    */
   static getIsTranslationsEngineSupported() {
+    try {
+      // Ensure WebAssembly is supported and enabled (may not be on tier-3).
+      if (!WebAssembly) {
+        return false;
+      }
+    } catch(e) {
+      return false;
+    }
+
     if (lazy.simulateUnsupportedEnginePref) {
       // Use the non-lazy console.log so that the user is always informed as to why
       // the translations engine is not working.
       console.log(
         "Translations: The translations engine is disabled through the pref " +
           '"browser.translations.simulateUnsupportedEngine".'
       );