diff --git a/TODO.md b/TODO.md
index fa567d5..198c70a 100644
--- a/TODO.md
+++ b/TODO.md
@@ -45,6 +45,16 @@ but the review is broader than any of them.
 
 # Completed Steps
 
+- 2026-10-05: A change made while an earlier save from the same page is still
+  running is stored ([#448](https://git.eeqj.de/sneak/AutistMask/issues/448)).
+  `saveStateOnce()` took its baseline from the page's state after the write, so
+  a change made while the save waited on storage counted as already stored and
+  the save queued after it wrote nothing. A setting changed during the read was
+  lost; so was a wallet added, a site revoked or an endpoint changed during the
+  write, and a wallet deleted then stayed in storage. The save now copies the
+  page's fields when it starts, writes from that copy, and keeps the copy as the
+  baseline.
+
 - 2026-10-05: The extension no longer opens a window for a site-connection
   prompt already answered
   ([#287](https://git.eeqj.de/sneak/AutistMask/issues/287)). When the prompt was
diff --git a/src/shared/state.js b/src/shared/state.js
index 2b6c78c..c580819 100644
--- a/src/shared/state.js
+++ b/src/shared/state.js
@@ -122,9 +122,9 @@ function currentNetwork() {
     return networkById(state.networkId);
 }
 
-// The persisted fields as they stood at the end of this page's last
-// loadState() or saveState(). saveState() diffs the live state against this
-// to find only the fields THIS page actually changed.
+// The persisted fields as this page held them when its last loadState()
+// finished, or when its last successful saveState() began. saveState() diffs
+// the live state against this to find only the fields THIS page changed since.
 //
 // Deep-cloned, not a reference: callers mutate persisted objects and arrays
 // in place (state.wallets.push(...)), and a reference baseline would mutate
@@ -464,7 +464,10 @@ function mergeNetworkEndpoints(base, ours, theirs) {
 // does not own goes on being whatever its last loadState() saw, same as
 // before this fix; only the persisted record is guaranteed current.
 async function saveStateOnce() {
-    const current = snapshotPersisted();
+    // A copy, so what this save compares and writes is the page's state as it
+    // stood when the save began. A change made while it waits on storage is
+    // left for the next save, which compares against this copy.
+    const current = structuredClone(snapshotPersisted());
     const result = await storageGet("autistmask");
     // The record in storage right now is about to be merged into and written
     // back, so it is validated exactly like a load validates it. Without this,
@@ -521,7 +524,11 @@ async function saveStateOnce() {
     // exactly as it stood; see the note above.
     rawState.hasWallet = rawState.wallets.length > 0;
 
-    baseline = structuredClone(snapshotPersisted());
+    // What this save compared and wrote, not the page's state now: a change
+    // made during the save must still differ from the baseline, or the save
+    // queued after it finds nothing to store
+    // (https://git.eeqj.de/sneak/AutistMask/issues/448).
+    baseline = current;
 }
 
 // showView() calls saveState() on every navigation without awaiting it, so
diff --git a/tests/stateMerge.test.js b/tests/stateMerge.test.js
index 66a6b1f..26756cc 100644
--- a/tests/stateMerge.test.js
+++ b/tests/stateMerge.test.js
@@ -423,3 +423,80 @@ describe("two wallets independently created with a colliding identity", () => {
         expect(secrets).toContain("secret-b");
     });
 });
+
+// showView() saves on every navigation without waiting, so the user can change
+// something while that save is still waiting on storage. The change is followed
+// by its own saveState(), which runs after the first save; it must be stored
+// (https://git.eeqj.de/sneak/AutistMask/issues/448).
+describe("a change made while an earlier save from the same page is running", () => {
+    // Runs `change` inside the next call to `op` (the stub's get or set),
+    // before that call does its work.
+    function runInside(op, change) {
+        const real = op.getMockImplementation();
+        op.mockImplementationOnce(async (arg) => {
+            change();
+            return real(arg);
+        });
+    }
+
+    test("a network switched during the earlier save's read is stored", async () => {
+        const storage = makeStorageStub({
+            autistmask: { wallets: [W1], networkId: "sepolia" },
+        });
+        const { state, saveState, loadState } = loadPage(storage).state;
+        await loadState();
+
+        let queued;
+        runInside(storage.get, () => {
+            state.networkId = "mainnet";
+            queued = saveState();
+        });
+        state.theme = "dark";
+        await saveState();
+        await queued;
+
+        const stored = storage.read("autistmask");
+        expect(stored.theme).toBe("dark");
+        expect(stored.networkId).toBe("mainnet");
+    });
+
+    test("a wallet added during the earlier save's read is stored", async () => {
+        const storage = makeStorageStub({ autistmask: { wallets: [W1] } });
+        const { state, saveState, loadState } = loadPage(storage).state;
+        await loadState();
+
+        let queued;
+        runInside(storage.get, () => {
+            state.wallets.push(W2);
+            queued = saveState();
+        });
+        await saveState();
+        await queued;
+
+        const stored = storage.read("autistmask");
+        expect(stored.wallets.map((w) => w.encryptedSecret)).toEqual([
+            "secret-one",
+            "secret-two",
+        ]);
+    });
+
+    test("a wallet added during the earlier save's write is stored", async () => {
+        const storage = makeStorageStub({ autistmask: { wallets: [W1] } });
+        const { state, saveState, loadState } = loadPage(storage).state;
+        await loadState();
+
+        let queued;
+        runInside(storage.set, () => {
+            state.wallets.push(W2);
+            queued = saveState();
+        });
+        await saveState();
+        await queued;
+
+        const stored = storage.read("autistmask");
+        expect(stored.wallets.map((w) => w.encryptedSecret)).toEqual([
+            "secret-one",
+            "secret-two",
+        ]);
+    });
+});