diff --git a/extension/src/browser/extension/inject/contentScript.ts b/extension/src/browser/extension/inject/contentScript.ts
index c1abac34..9e9d3732 100644
--- a/extension/src/browser/extension/inject/contentScript.ts
+++ b/extension/src/browser/extension/inject/contentScript.ts
@@ -212,7 +212,10 @@ function tryCatch<S, A extends Action<unknown>>(
   try {
     return fn(args);
   } catch (err) {
-    if (err.message === 'Message length exceeded maximum allowed length.') {
+    if (
+      (err as Error).message ===
+      'Message length exceeded maximum allowed length.'
+    ) {
       const instanceId = (args as any).instanceId;
       const newArgs = {
         split: 'start',
diff --git a/extension/src/browser/extension/inject/pageScript.ts b/extension/src/browser/extension/inject/pageScript.ts
index eec0472e..e3c9fa7a 100644
--- a/extension/src/browser/extension/inject/pageScript.ts
+++ b/extension/src/browser/extension/inject/pageScript.ts
@@ -397,7 +397,7 @@ function __REDUX_DEVTOOLS_EXTENSION__<S, A extends Action<unknown>>(
       toContentScript(
         {
           type: 'ERROR',
-          payload: e.message,
+          payload: (e as Error).message,
           source,
           instanceId,
         },
@@ -417,7 +417,7 @@ function __REDUX_DEVTOOLS_EXTENSION__<S, A extends Action<unknown>>(
       toContentScript(
         {
           type: 'ERROR',
-          payload: e.message,
+          payload: (e as Error).message,
           source,
           instanceId,
         },