diff --git a/src/ContentMessages.ts b/src/ContentMessages.ts
index f7e7b5277c..a2fe27d0a9 100644
--- a/src/ContentMessages.ts
+++ b/src/ContentMessages.ts
@@ -303,6 +303,7 @@ export async function uploadFile(
             progressHandler,
             abortController,
             includeFilename: false,
+            type: "application/octet-stream",
         });
         if (abortController.signal.aborted) throw new UploadCanceledError();
 
diff --git a/test/ContentMessages-test.ts b/test/ContentMessages-test.ts
index e2a4797791..5bfc9c315f 100644
--- a/test/ContentMessages-test.ts
+++ b/test/ContentMessages-test.ts
@@ -312,6 +312,7 @@ describe("uploadFile", () => {
             expect.objectContaining({
                 progressHandler,
                 includeFilename: false,
+                type: "application/octet-stream",
             }),
         );
         expect(mocked(client.uploadContent).mock.calls[0][0]).not.toBe(file);