diff --git a/CHANGELOG.md b/CHANGELOG.md
index 444b7916fe6..6b0b8379ff5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## Unreleased
+
+* Undo an earlier change to try to improve yarn compatibility ([#91](https://github.com/evanw/esbuild/pull/91) and [#407](https://github.com/evanw/esbuild/issues/407))
+
+    The [yarn package manager](https://github.com/yarnpkg/yarn) behaves differently from npm and is not compatible in many ways. While npm is the only officially supported package manager for esbuild, people have contributed fixes for other package managers including yarn. One such fix is PR [#91](https://github.com/evanw/esbuild/pull/91) which makes sure the install script only runs once for a given installation directory.
+
+    I suspect this fix is actually incorrect, and is the cause of issue [#407](https://github.com/evanw/esbuild/issues/407). The problem seems to be that if you change the version of a package using `yarn add esbuild@version`, yarn doesn't clear out the installation directory before reinstalling the package so the package ends up with a mix of files from both package versions. This is not how npm behaves and seems like a pretty severe bug in yarn. I am reverting PR [#91](https://github.com/evanw/esbuild/pull/91) in an attempt to fix this issue.
+
 ## 0.7.3
 
 * Fix compile error due to missing `unix.SYS_IOCTL` in the latest `golang.org/x/sys` ([#396](https://github.com/evanw/esbuild/pull/396))
diff --git a/lib/install.ts b/lib/install.ts
index 2ac93e38203..c7e9672ae7c 100644
--- a/lib/install.ts
+++ b/lib/install.ts
@@ -9,17 +9,8 @@ declare const ESBUILD_VERSION: string;
 
 const version = ESBUILD_VERSION;
 const binPath = path.join(__dirname, 'bin', 'esbuild');
-const stampPath = path.join(__dirname, 'stamp.txt');
 
 async function installBinaryFromPackage(name: string, fromPath: string, toPath: string): Promise<void> {
-  // It turns out that some package managers (e.g. yarn) sometimes re-run the
-  // postinstall script for this package after we have already been installed.
-  // That means this script must be idempotent. Let's skip the install if it's
-  // already happened.
-  if (fs.existsSync(stampPath)) {
-    return;
-  }
-
   // Try to install from the cache if possible
   const cachePath = getCachePath(name);
   try {
@@ -33,9 +24,6 @@ async function installBinaryFromPackage(name: string, fromPath: string, toPath:
     // Mark the cache entry as used for LRU
     const now = new Date;
     fs.utimesSync(cachePath, now, now);
-
-    // Mark the operation as successful so this script is idempotent
-    fs.writeFileSync(stampPath, '');
     return;
   } catch {
   }
@@ -83,9 +71,6 @@ async function installBinaryFromPackage(name: string, fromPath: string, toPath:
     process.exit(1);
   }
 
-  // Mark the operation as successful so this script is idempotent
-  fs.writeFileSync(stampPath, '');
-
   // Also try to cache the file to speed up future installs
   try {
     fs.mkdirSync(path.dirname(cachePath), { recursive: true });
@@ -172,7 +157,7 @@ function extractFileFromTarGzip(buffer: Buffer, file: string): Buffer {
 
 function installUsingNPM(name: string, file: string): Buffer {
   const installDir = path.join(__dirname, '.install');
-  fs.mkdirSync(installDir);
+  fs.mkdirSync(installDir, { recursive: true });
   fs.writeFileSync(path.join(installDir, 'package.json'), '{}');
 
   // Erase "npm_config_global" so that "npm install --global esbuild" works.