diff --git a/server/src/adapters/plugin-loader.ts b/server/src/adapters/plugin-loader.ts
index a9f704635d..c01fedeac4 100644
--- a/server/src/adapters/plugin-loader.ts
+++ b/server/src/adapters/plugin-loader.ts
@@ -11,6 +11,7 @@
 
 import fs from "node:fs";
 import path from "node:path";
+import { pathToFileURL } from "node:url";
 import type { ServerAdapterModule } from "./types.js";
 import { logger } from "../middleware/logger.js";
 
@@ -177,7 +178,7 @@ export async function loadExternalAdapterPackage(
 
   logger.info({ packageName, packageDir, entryPoint, modulePath, hasUiParser: !!uiParserSource }, "Loading external adapter package");
 
-  const mod = await import(modulePath);
+  const mod = await import(pathToFileURL(modulePath).href);
   const adapterModule = validateAdapterModule(mod, packageName);
 
   if (uiParserSource) {
@@ -212,7 +213,7 @@ export async function reloadExternalAdapter(
   const packageDir = resolvePackageDir(record);
   const entryPoint = resolvePackageEntryPoint(packageDir);
   const modulePath = path.resolve(packageDir, entryPoint);
-  const fileUrl = `file://${modulePath}`;
+  const fileUrl = pathToFileURL(modulePath).href;
 
   // Bust ESM module cache so re-import loads fresh code from disk.
   // Query-string trick (?t=...) works in Node; Bun may need the file:// URL