diff --git a/packages/core/useMounted/index.ts b/packages/core/useMounted/index.ts
index dd2cfec8f9b..04fe8d43046 100644
--- a/packages/core/useMounted/index.ts
+++ b/packages/core/useMounted/index.ts
@@ -13,7 +13,7 @@ export function useMounted() {
   if (instance) {
     onMounted(() => {
       isMounted.value = true
-    }, isVue2 ? null : instance)
+    }, isVue2 ? undefined : instance)
   }
 
   return isMounted
diff --git a/packages/nuxt/README.md b/packages/nuxt/README.md
index bb0d8f7a009..94460aa3bc2 100644
--- a/packages/nuxt/README.md
+++ b/packages/nuxt/README.md
@@ -7,7 +7,7 @@
 ## Install
 
 ```bash
-npm i @vueuse/nuxt
+npm i @vueuse/nuxt @vueuse/core
 ```
 
 ```ts
diff --git a/packages/nuxt/ssr-plugin.mjs b/packages/nuxt/ssr-plugin.mjs
index c824e742ebb..cc0fb046bc4 100644
--- a/packages/nuxt/ssr-plugin.mjs
+++ b/packages/nuxt/ssr-plugin.mjs
@@ -15,7 +15,7 @@ setSSRHandler('getDefaultStorage', () => {
   }
 })
 
-if (process.server) {
+if (import.meta.server) {
   setSSRHandler('updateHTMLAttrs', (selector, attr, value) => {
     if (selector === 'html') {
       useHead({