diff --git a/packages/typescript-plugin/lib/server.ts b/packages/typescript-plugin/lib/server.ts
index 0234ca0af9..d8fc0983b1 100644
--- a/packages/typescript-plugin/lib/server.ts
+++ b/packages/typescript-plugin/lib/server.ts
@@ -44,7 +44,7 @@ export function startNamedPipeServer(
 			const text = data.toString();
 			const request: Request = JSON.parse(text);
 			const fileName = request.args[0];
-			const project = getProject(fileName);
+			const project = getProject(ts.server.toNormalizedPath(fileName));
 			if (request.type === 'projectInfoForFile') {
 				connection.write(
 					JSON.stringify(
@@ -154,9 +154,9 @@ export const projects = new Map<ts.server.Project, {
 	vueOptions: VueCompilerOptions;
 }>();
 
-function getProject(fileName: string) {
+function getProject(filename: ts.server.NormalizedPath) {
 	for (const [project, data] of projects) {
-		if (project.containsFile(fileName as ts.server.NormalizedPath)) {
+		if (project.containsFile(filename)) {
 			return data;
 		}
 	}