diff --git a/extensions/html-language-features/client/src/customData.ts b/extensions/html-language-features/client/src/customData.ts
index 248ad18672c..146fef2f3ee 100644
--- a/extensions/html-language-features/client/src/customData.ts
+++ b/extensions/html-language-features/client/src/customData.ts
@@ -4,7 +4,8 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { workspace, extensions, Uri, EventEmitter, Disposable } from 'vscode';
-import { resolvePath, joinPath } from './requests';
+import { resolvePath, joinPath, uriScheme } from './requests';
+
 
 export function getCustomDataSource(toDispose: Disposable[]) {
 	let pathsInWorkspace = getCustomDataPathsInAllWorkspaces();
@@ -57,8 +58,7 @@ function getCustomDataPathsInAllWorkspaces(): Set<string> {
 		if (Array.isArray(paths)) {
 			for (const path of paths) {
 				if (typeof path === 'string') {
-					const uri = Uri.parse(path);
-					if (uri.scheme === 'file') {
+					if (!uriScheme.test(path)) {
 						// only resolve file paths relative to extension
 						dataPaths.add(resolvePath(rootFolder, path).toString());
 					} else {
@@ -94,12 +94,11 @@ function getCustomDataPathsFromAllExtensions(): Set<string> {
 		const customData = extension.packageJSON?.contributes?.html?.customData;
 		if (Array.isArray(customData)) {
 			for (const rp of customData) {
-				const uri = Uri.parse(rp);
-				if (uri.scheme === 'file') {
-					// only resolve file paths relative to extension
+				if (!uriScheme.test(rp)) {
+					// no schame -> resolve relative to extension
 					dataPaths.add(joinPath(extension.extensionUri, rp).toString());
 				} else {
-					// others schemes
+					// actual schemes
 					dataPaths.add(rp);
 				}
 
diff --git a/extensions/html-language-features/client/src/requests.ts b/extensions/html-language-features/client/src/requests.ts
index e5bc857dabd..aa75e6b615f 100644
--- a/extensions/html-language-features/client/src/requests.ts
+++ b/extensions/html-language-features/client/src/requests.ts
@@ -7,6 +7,8 @@ import { Uri, workspace } from 'vscode';
 import { RequestType, CommonLanguageClient } from 'vscode-languageclient';
 import { Runtime } from './htmlClient';
 
+export const uriScheme = /^(?<scheme>\w[\w\d+.-]*):/;
+
 export namespace FsContentRequest {
 	export const type: RequestType<{ uri: string; encoding?: string; }, string, any> = new RequestType('fs/content');
 }
@@ -20,34 +22,34 @@ export namespace FsReadDirRequest {
 
 export function serveFileSystemRequests(client: CommonLanguageClient, runtime: Runtime, subscriptions: { dispose(): any }[]) {
 	subscriptions.push(client.onRequest(FsContentRequest.type, (param: { uri: string; encoding?: string; }) => {
-		const uri = Uri.parse(param.uri);
-		if (uri.scheme === 'file') {
+		const uri = param.uri.match(uriScheme);
+		if (uri?.groups?.scheme === 'file') {
 			if (runtime.fs) {
 				return runtime.fs.getContent(param.uri);
 			} else {
-				return workspace.fs.readFile(uri).then(buffer => {
+				return workspace.fs.readFile(Uri.parse(param.uri)).then(buffer => {
 					return new runtime.TextDecoder(param.encoding).decode(buffer);
 				});
 			}
 		} else {
-			return workspace.openTextDocument(uri).then(doc => {
+			return workspace.openTextDocument(Uri.parse(param.uri)).then(doc => {
 				return doc.getText();
 			});
 		}
 	}));
 	subscriptions.push(client.onRequest(FsReadDirRequest.type, (uriString: string) => {
-		const uri = Uri.parse(uriString);
-		if (uri.scheme === 'file' && runtime.fs) {
+		const uri = uriString.match(uriScheme);
+		if (uri?.groups?.scheme === 'file' && runtime.fs) {
 			return runtime.fs.readDirectory(uriString);
 		}
-		return workspace.fs.readDirectory(uri);
+		return workspace.fs.readDirectory(Uri.parse(uriString));
 	}));
 	subscriptions.push(client.onRequest(FsStatRequest.type, (uriString: string) => {
-		const uri = Uri.parse(uriString);
-		if (uri.scheme === 'file' && runtime.fs) {
+		const uri = uriString.match(uriScheme);
+		if (uri?.groups?.scheme === 'file' && runtime.fs) {
 			return runtime.fs.stat(uriString);
 		}
-		return workspace.fs.stat(uri);
+		return workspace.fs.stat(Uri.parse(uriString));
 	}));
 }