diff --git a/apps/desktop/src/updateState.test.ts b/apps/desktop/src/updateState.test.ts
index c2bb4ba1..181c4d55 100644
--- a/apps/desktop/src/updateState.test.ts
+++ b/apps/desktop/src/updateState.test.ts
@@ -116,6 +116,19 @@ describe("getAutoUpdateDisabledReason", () => {
     ).toContain("T3CODE_DISABLE_AUTO_UPDATE");
   });
 
+  it("explains that env-disabled updates can come from package-managed installs", () => {
+    expect(
+      getAutoUpdateDisabledReason({
+        isDevelopment: false,
+        isPackaged: true,
+        platform: "linux",
+        appImage: undefined,
+        disabledByEnv: true,
+        hasUpdateFeedConfig: true,
+      }),
+    ).toContain("Nix");
+  });
+
   it("reports linux non-AppImage builds as disabled", () => {
     expect(
       getAutoUpdateDisabledReason({
diff --git a/apps/desktop/src/updateState.ts b/apps/desktop/src/updateState.ts
index 928bb408..9ebdf331 100644
--- a/apps/desktop/src/updateState.ts
+++ b/apps/desktop/src/updateState.ts
@@ -43,7 +43,7 @@ export function getAutoUpdateDisabledReason(args: {
     return "Automatic updates are only available in packaged production builds.";
   }
   if (args.disabledByEnv) {
-    return "Automatic updates are disabled by the T3CODE_DISABLE_AUTO_UPDATE setting.";
+    return "Automatic updates are disabled by the T3CODE_DISABLE_AUTO_UPDATE setting, which is used for package-managed installs such as Nix.";
   }
   if (args.platform === "linux" && !args.appImage) {
     return "Automatic updates on Linux require running the AppImage build.";