diff --git a/src/serviceModules/FileSystemAdapters/ObsidianStorageAdapter.unit.spec.ts b/src/serviceModules/FileSystemAdapters/ObsidianStorageAdapter.unit.spec.ts
new file mode 100644
index 00000000..7172879f
--- /dev/null
+++ b/src/serviceModules/FileSystemAdapters/ObsidianStorageAdapter.unit.spec.ts
@@ -0,0 +1,32 @@
+import { describe, expect, it, vi } from "vitest";
+import type { App } from "obsidian";
+import { ObsidianStorageAdapter } from "./ObsidianStorageAdapter";
+
+describe("ObsidianStorageAdapter", () => {
+    it("floors write-option timestamps before calling Obsidian storage methods", async () => {
+        const write = vi.fn().mockResolvedValue(undefined);
+        const writeBinary = vi.fn().mockResolvedValue(undefined);
+        const append = vi.fn().mockResolvedValue(undefined);
+        const app = {
+            vault: {
+                adapter: {
+                    write,
+                    writeBinary,
+                    append,
+                },
+            },
+        } as unknown as App;
+        const adapter = new ObsidianStorageAdapter(app);
+        const options = { ctime: 1778511180024.462, mtime: 1778511180999.913 };
+        const expectedOptions = { ctime: 1778511180024, mtime: 1778511180999 };
+
+        await adapter.write("note.md", "text", options);
+        await adapter.writeBinary("image.bin", new ArrayBuffer(0), options);
+        await adapter.append("log.md", "text", options);
+
+        expect(write).toHaveBeenCalledWith("note.md", "text", expectedOptions);
+        expect(writeBinary).toHaveBeenCalledWith("image.bin", expect.any(ArrayBuffer), expectedOptions);
+        expect(append).toHaveBeenCalledWith("log.md", "text", expectedOptions);
+        expect(options).toEqual({ ctime: 1778511180024.462, mtime: 1778511180999.913 });
+    });
+});
diff --git a/src/serviceModules/FileSystemAdapters/ObsidianVaultAdapter.unit.spec.ts b/src/serviceModules/FileSystemAdapters/ObsidianVaultAdapter.unit.spec.ts
index 5a307d52..0c22f212 100644
--- a/src/serviceModules/FileSystemAdapters/ObsidianVaultAdapter.unit.spec.ts
+++ b/src/serviceModules/FileSystemAdapters/ObsidianVaultAdapter.unit.spec.ts
@@ -2,7 +2,7 @@ import { describe, expect, it, vi } from "vitest";
 import type { App, TFile } from "obsidian";
 import { ObsidianVaultAdapter } from "./ObsidianVaultAdapter";
 
-describe("ObsidianVaultAdapter.read", () => {
+describe("ObsidianVaultAdapter", () => {
     it("preserves a UTF-8 BOM so the content size matches the file stat", async () => {
         const path = "Transcripts/字幕.md";
         const contentWithoutBom = "字幕の検証行です。\n";
@@ -34,4 +34,34 @@ describe("ObsidianVaultAdapter.read", () => {
         expect(adapterRead).toHaveBeenCalledWith(path);
         expect(read).not.toHaveBeenCalled();
     });
+
+    it("floors write-option timestamps before calling Obsidian vault methods", async () => {
+        const modify = vi.fn().mockResolvedValue(undefined);
+        const modifyBinary = vi.fn().mockResolvedValue(undefined);
+        const create = vi.fn().mockResolvedValue({});
+        const createBinary = vi.fn().mockResolvedValue({});
+        const app = {
+            vault: {
+                modify,
+                modifyBinary,
+                create,
+                createBinary,
+            },
+        } as unknown as App;
+        const file = { path: "note.md" } as TFile;
+        const adapter = new ObsidianVaultAdapter(app);
+        const options = { ctime: 1778511180024.462, mtime: 1778511180999.913 };
+        const expectedOptions = { ctime: 1778511180024, mtime: 1778511180999 };
+
+        await adapter.modify(file, "text", options);
+        await adapter.modifyBinary(file, new ArrayBuffer(0), options);
+        await adapter.create("created.md", "text", options);
+        await adapter.createBinary("created.bin", new ArrayBuffer(0), options);
+
+        expect(modify).toHaveBeenCalledWith(file, "text", expectedOptions);
+        expect(modifyBinary).toHaveBeenCalledWith(file, expect.any(ArrayBuffer), expectedOptions);
+        expect(create).toHaveBeenCalledWith("created.md", "text", expectedOptions);
+        expect(createBinary).toHaveBeenCalledWith("created.bin", expect.any(ArrayBuffer), expectedOptions);
+        expect(options).toEqual({ ctime: 1778511180024.462, mtime: 1778511180999.913 });
+    });
 });
diff --git a/src/serviceModules/FileSystemAdapters/sanitizeWriteOptions.ts b/src/serviceModules/FileSystemAdapters/sanitizeWriteOptions.ts
index 4cb92355..3c055c16 100644
--- a/src/serviceModules/FileSystemAdapters/sanitizeWriteOptions.ts
+++ b/src/serviceModules/FileSystemAdapters/sanitizeWriteOptions.ts
@@ -1,4 +1,4 @@
-import type { UXDataWriteOptions } from "@lib/common/types";
+import type { UXDataWriteOptions } from "@vrtmrz/livesync-commonlib/compat/common/types";
 
 /**
  * Coerce the timestamp fields of a write-options object to integer milliseconds.