diff --git a/server/routes/api/collections/collections.ts b/server/routes/api/collections/collections.ts
index acb437a222..a38ef02313 100644
--- a/server/routes/api/collections/collections.ts
+++ b/server/routes/api/collections/collections.ts
@@ -875,6 +875,7 @@ router.post(
 
     const collection = await Collection.findByPk(id, {
       transaction,
+      lock: transaction.LOCK.UPDATE,
     });
     authorize(user, "move", collection);
 
diff --git a/server/utils/removeIndexCollision.test.ts b/server/utils/removeIndexCollision.test.ts
new file mode 100644
index 0000000000..bba295e0a1
--- /dev/null
+++ b/server/utils/removeIndexCollision.test.ts
@@ -0,0 +1,16 @@
+import { buildCollection } from "@server/test/factories";
+import removeIndexCollision from "./removeIndexCollision";
+
+describe("removeIndexCollision", () => {
+  it("should return the next available index", async () => {
+    const collection = await buildCollection({ index: "P" });
+    expect(
+      await removeIndexCollision(collection.teamId, collection.index!)
+    ).toEqual("h");
+  });
+
+  it("should return existing index if no collision", async () => {
+    const collection = await buildCollection({ index: "%P" });
+    expect(await removeIndexCollision(collection.teamId, "n")).toEqual("n");
+  });
+});