diff --git a/electron/saveDataBinaryFormat.d.ts b/electron/saveDataBinaryFormat.d.ts
index 183582233..747b50f12 100644
--- a/electron/saveDataBinaryFormat.d.ts
+++ b/electron/saveDataBinaryFormat.d.ts
@@ -1 +1 @@
-export declare const isBinaryFormat: (saveData: string | Uint8Array) => boolean;
+export declare const isBinaryFormat: (saveData: string | Uint8Array<ArrayBuffer>) => boolean;
diff --git a/markdown/bitburner.singularity.getsavedata.md b/markdown/bitburner.singularity.getsavedata.md
index e48925b28..65491bc0e 100644
--- a/markdown/bitburner.singularity.getsavedata.md
+++ b/markdown/bitburner.singularity.getsavedata.md
@@ -9,11 +9,11 @@ This function returns the save data.
 **Signature:**
 
 ```typescript
-getSaveData(): Promise<Uint8Array>;
+getSaveData(): Promise<Uint8Array<ArrayBuffer>>;
 ```
 **Returns:**
 
-Promise&lt;Uint8Array&gt;
+Promise&lt;Uint8Array&lt;ArrayBuffer&gt;&gt;
 
 ## Remarks
 
diff --git a/package-lock.json b/package-lock.json
index 03e7dc97f..009e29724 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -96,7 +96,7 @@
         "prettier": "^2.8.8",
         "react-refresh": "^0.18.0",
         "style-loader": "^4.0.0",
-        "typescript": "^5.8.3",
+        "typescript": "^5.9.3",
         "webpack": "^5.100.2",
         "webpack-cli": "^6.0.1",
         "webpack-dev-server": "^5.2.2",
@@ -18081,9 +18081,9 @@
       }
     },
     "node_modules/typescript": {
-      "version": "5.8.3",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.8.3.tgz",
-      "integrity": "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==",
+      "version": "5.9.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.9.3.tgz",
+      "integrity": "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==",
       "dev": true,
       "license": "Apache-2.0",
       "bin": {
diff --git a/package.json b/package.json
index 1ce42cbd2..53ce10849 100644
--- a/package.json
+++ b/package.json
@@ -97,7 +97,7 @@
     "prettier": "^2.8.8",
     "react-refresh": "^0.18.0",
     "style-loader": "^4.0.0",
-    "typescript": "^5.8.3",
+    "typescript": "^5.9.3",
     "webpack": "^5.100.2",
     "webpack-cli": "^6.0.1",
     "webpack-dev-server": "^5.2.2",
diff --git a/src/Electron.tsx b/src/Electron.tsx
index ab37bbea0..c78a91b51 100644
--- a/src/Electron.tsx
+++ b/src/Electron.tsx
@@ -10,6 +10,7 @@ import { exportScripts } from "./Terminal/commands/download";
 import { CONSTANTS } from "./Constants";
 import { commitHash } from "./utils/helpers/commitHash";
 import { handleGetSaveDataInfoError } from "./utils/ErrorHandler";
+import { assertSaveData } from "./utils/TypeAssertion";
 
 interface IReturnWebStatus extends IReturnStatus {
   data?: Record<string, unknown>;
@@ -122,9 +123,7 @@ function initElectronBridge(): void {
       });
   });
   bridge.receive("get-save-info-request", (saveData: unknown) => {
-    if (typeof saveData !== "string" && !(saveData instanceof Uint8Array)) {
-      throw new Error("Error while trying to get save info");
-    }
+    assertSaveData(saveData);
     window.appSaveFns
       .getSaveInfo(saveData)
       .then((saveInfo) => {
diff --git a/src/ScriptEditor/NetscriptDefinitions.d.ts b/src/ScriptEditor/NetscriptDefinitions.d.ts
index 5792ee5c9..cbc4bb98d 100644
--- a/src/ScriptEditor/NetscriptDefinitions.d.ts
+++ b/src/ScriptEditor/NetscriptDefinitions.d.ts
@@ -1879,7 +1879,7 @@ export interface Singularity {
    * @remarks
    * RAM cost: 1 GB * 16/4/1
    */
-  getSaveData(): Promise<Uint8Array>;
+  getSaveData(): Promise<Uint8Array<ArrayBuffer>>;
 
   /**
    * Backup game save.
diff --git a/src/types.ts b/src/types.ts
index 384bbdd8d..39e218b42 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -46,4 +46,4 @@ export interface IMinMaxRange {
 }
 
 // Type of save data. The base64 format is string, the binary format is Uint8Array.
-export type SaveData = string | Uint8Array;
+export type SaveData = string | Uint8Array<ArrayBuffer>;
diff --git a/src/utils/SaveDataUtils.ts b/src/utils/SaveDataUtils.ts
index e4bc60a8d..d62f942f8 100644
--- a/src/utils/SaveDataUtils.ts
+++ b/src/utils/SaveDataUtils.ts
@@ -15,12 +15,12 @@ export function canUseBinaryFormat(): boolean {
   return "CompressionStream" in globalThis;
 }
 
-async function compress(dataString: string): Promise<Uint8Array> {
+async function compress(dataString: string): Promise<Uint8Array<ArrayBuffer>> {
   const compressedReadableStream = new Blob([dataString]).stream().pipeThrough(new CompressionStream("gzip"));
   return new Uint8Array(await new Response(compressedReadableStream).arrayBuffer());
 }
 
-async function decompress(binaryData: Uint8Array): Promise<string> {
+async function decompress(binaryData: Uint8Array<ArrayBuffer>): Promise<string> {
   const decompressedReadableStream = new Blob([binaryData]).stream().pipeThrough(new DecompressionStream("gzip"));
   const reader = decompressedReadableStream.pipeThrough(new TextDecoderStream("utf-8", { fatal: true })).getReader();
   let result = "";
diff --git a/src/utils/TypeAssertion.ts b/src/utils/TypeAssertion.ts
index 0b7312d80..018ef2a73 100644
--- a/src/utils/TypeAssertion.ts
+++ b/src/utils/TypeAssertion.ts
@@ -1,4 +1,4 @@
-import type { Unknownify } from "../types";
+import type { SaveData, Unknownify } from "../types";
 
 // This function is empty because Unknownify<T> is a typesafe assertion on any object with no runtime checks needed.
 // eslint-disable-next-line @typescript-eslint/no-empty-function
@@ -89,3 +89,14 @@ export function assertNumberArray(unknownData: unknown, assertFinite = false): a
     }
   }
 }
+
+export function assertSaveData(unknownData: unknown): asserts unknownData is SaveData {
+  if (typeof unknownData !== "string" && !(unknownData instanceof Uint8Array)) {
+    console.error(unknownData);
+    throw new Error(`Invalid save data. Its type is ${getFriendlyType(unknownData)}.`);
+  }
+  if (unknownData instanceof Uint8Array && !(unknownData.buffer instanceof ArrayBuffer)) {
+    console.error(unknownData);
+    throw new Error("Invalid save data. It's Uint8Array, but its buffer is not ArrayBuffer.");
+  }
+}