diff --git a/.changeset/fix-windows-preview-path-to-file-url.md b/.changeset/fix-windows-preview-path-to-file-url.md
new file mode 100644
index 000000000..a007cc505
--- /dev/null
+++ b/.changeset/fix-windows-preview-path-to-file-url.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+Convert absolute path to file:// URL before dynamic import in preview server to fix Windows compatibility
diff --git a/packages/start/src/config/dev-server.ts b/packages/start/src/config/dev-server.ts
index d88a8cb0d..3b2ad6ae6 100644
--- a/packages/start/src/config/dev-server.ts
+++ b/packages/start/src/config/dev-server.ts
@@ -1,4 +1,5 @@
 import { NodeRequest, sendNodeResponse } from "srvx/node";
+import { pathToFileURL } from "node:url";
 import {
   type Connect,
   isRunnableDevEnvironment,
@@ -18,7 +19,7 @@ export function devServer(): Array<PluginOption> {
             const webReq = new NodeRequest({ req, res });
             const def: {
               default: { fetch: (req: Request) => Promise<Response> };
-            } = await import(process.cwd() + "/dist/server/entry-server.js");
+            } = await import(pathToFileURL(process.cwd() + "/dist/server/entry-server.js").href);
             sendNodeResponse(res, await def.default.fetch(webReq));
           });
         };
diff --git a/packages/start/src/config/index.ts b/packages/start/src/config/index.ts
index 9cdc6830e..c0ae98d9f 100644
--- a/packages/start/src/config/index.ts
+++ b/packages/start/src/config/index.ts
@@ -200,6 +200,30 @@ export function solidStart(options?: SolidStartOptions): Array<PluginOption> {
       },
       filter: options?.serverFunctions?.filter,
     }),
+    {
+      name: "solid-start:boundary-modules",
+      resolveId(id, importer, { ssr }) {
+        if (id === "server-only") {
+          if (!ssr) {
+            this.error(
+              `[server-only] "${importer}" cannot import a server-only module on the client`,
+            );
+          }
+          return "\0server-only";
+        }
+        if (id === "client-only") {
+          if (ssr) {
+            this.error(
+              `[client-only] "${importer}" cannot import a client-only module on the server`,
+            );
+          }
+          return "\0client-only";
+        }
+      },
+      load(id) {
+        if (id === "\0server-only" || id === "\0client-only") return "export {}";
+      },
+    },
     {
       name: "solid-start:virtual-modules",
       async resolveId(id) {
diff --git a/packages/start/src/server/handler.ts b/packages/start/src/server/handler.ts
index 9b1c9f218..f08f1f41c 100644
--- a/packages/start/src/server/handler.ts
+++ b/packages/start/src/server/handler.ts
@@ -114,12 +114,15 @@ export function createBaseHandler(
 
       if (mode === "async") return await stream;
 
-      delete (stream as any).then;
-
       // using TransformStream in dev can cause solid-start-dev-server to crash
       // when stream is cancelled
       if (globalThis.USING_SOLID_START_DEV_SERVER) return stream;
 
+      // remove thenable so h3/Cloudflare Workers do not await the stream object;
+      // must happen after the dev-server branch so the stream remains awaitable
+      // when returned to solid-start-dev-server above
+      delete (stream as any).then;
+
       // returning stream directly breaks cloudflare workers
       const { writable, readable } = new TransformStream();
       stream.pipeTo(writable);