diff --git a/src/server/index.ts b/src/server/index.ts
index 160bce2..6744848 100644
--- a/src/server/index.ts
+++ b/src/server/index.ts
@@ -100,14 +100,14 @@ export default class TsserverService implements IServiceProvider {
   }
 
   public async start(): Promise<void> {
-    if (!this.enable) return
+    if (!this.enable || this._state == ServiceStat.Starting) return
+    this._state = ServiceStat.Starting
     if (this.clientHost) {
       let client = this.clientHost.serviceClient
       client.restartTsServer()
       return
     }
-    let tscPath = await workspace.nvim.getVar('Tsserver_path') as string
-    this._state = ServiceStat.Starting
+    let tscPath = await workspace.nvim.getVar('Tsserver_path') as string | null
     this.clientHost = new TypeScriptServiceClientHost(this.descriptions, this.pluginManager, tscPath)
     let client = this.clientHost.serviceClient
     await new Promise(resolve => {
@@ -132,7 +132,7 @@ export default class TsserverService implements IServiceProvider {
     if (!this.clientHost) return
     let client = this.clientHost.serviceClient
     await client.stop()
-    this.clientHost.dispose()
+    this.clientHost?.dispose()
     this.clientHost = null
     this._state = ServiceStat.Stopped
   }
diff --git a/src/server/typescriptServiceClientHost.ts b/src/server/typescriptServiceClientHost.ts
index 4113e09..dd44d49 100644
--- a/src/server/typescriptServiceClientHost.ts
+++ b/src/server/typescriptServiceClientHost.ts
@@ -38,7 +38,7 @@ export default class TypeScriptServiceClientHost implements Disposable {
   private readonly fileConfigurationManager: FileConfigurationManager
   private reportStyleCheckAsWarnings = true
 
-  constructor(descriptions: LanguageDescription[], pluginManager: PluginManager, tscPath: string | undefined) {
+  constructor(descriptions: LanguageDescription[], pluginManager: PluginManager, tscPath: string | null) {
     let timer: NodeJS.Timer
     const handleProjectChange = () => {
       if (timer) clearTimeout(timer)