diff --git a/evm-config.schema.json b/evm-config.schema.json
index fb366a24..f72b5153 100644
--- a/evm-config.schema.json
+++ b/evm-config.schema.json
@@ -12,6 +12,12 @@
       "type": "string",
       "default": "electron"
     },
+    "preserveSDK": {
+      "description": "Preserve the N most recent Xcode SDK versions",
+      "type": "integer",
+      "default": 5,
+      "minimum": 1
+    },
     "execName": {
       "description": "Name of the built executable to run",
       "type": "string",
diff --git a/example-configs/evm.base.yml b/example-configs/evm.base.yml
index 696f823e..25220255 100644
--- a/example-configs/evm.base.yml
+++ b/example-configs/evm.base.yml
@@ -1,5 +1,6 @@
 root: /path/to/your/developer/folder
 reclient: remote_exec
+preserveSDK: 5
 remotes:
   electron:
     # SSH or HTTPS url
diff --git a/src/e-init.js b/src/e-init.js
index 9ac6ff04..fcff185b 100644
--- a/src/e-init.js
+++ b/src/e-init.js
@@ -67,6 +67,7 @@ function createConfig(options) {
       args: gn_args,
       out: options.out,
     },
+    preserveSDK: 5,
     env: {
       CHROMIUM_BUILDTOOLS_PATH: path.resolve(root, 'src', 'buildtools'),
       GIT_CACHE_PATH: process.env.GIT_CACHE_PATH
@@ -167,15 +168,6 @@ program
         checkGlobalGitConfig();
       }
 
-      // ensure xcode is loaded
-      if (process.platform === 'darwin') {
-        if (options.onlySdk) {
-          ensureSDK();
-        } else {
-          loadXcode();
-        }
-      }
-
       // ensure macOS SDKs are loaded
       if (process.platform === 'darwin') {
         ensureSDK();
diff --git a/src/evm-config.js b/src/evm-config.js
index 283dc85e..fef0b844 100644
--- a/src/evm-config.js
+++ b/src/evm-config.js
@@ -215,11 +215,21 @@ function sanitizeConfig(name, config, overwrite = false) {
     changes.push(`fixed invalid property ${color.config('reclient: none')}`);
   }
 
-  if ('preserveXcode' in config) {
+  if (config.preserveXcode) {
     delete config.preserveXcode;
     changes.push(`removed ${color.config('preserveXcode')} property`);
   }
 
+  if (config.onlySdk) {
+    delete config.onlySdk;
+    changes.push(`removed ${color.config('onlySdk')} property`);
+  }
+
+  if (!('preserveSDK' in config)) {
+    config.preserveSDK = 5;
+    changes.push(`added ${color.config('preserveSDK')} property`);
+  }
+
   if (config.goma) {
     delete config.goma;
     changes.push(`removed deprecated ${color.config('goma')} property`);
diff --git a/src/utils/sdk.js b/src/utils/sdk.js
index a719aadd..c0e3f400 100644
--- a/src/utils/sdk.js
+++ b/src/utils/sdk.js
@@ -58,6 +58,22 @@ function getSDKVersion() {
   return json.MinimalDisplayName;
 }
 
+function removeUnusedSDKs() {
+  const recent = fs
+    .readdirSync(SDKDir)
+    .map(sdk => {
+      const sdkPath = path.join(SDKDir, sdk);
+      const { atime } = fs.statSync(sdkPath);
+      return { name: xcodePath, atime };
+    })
+    .sort((a, b) => b.atime - a.atime);
+
+  const { preserveSDK } = evmConfig.current();
+  for (const { name } of recent.slice(preserveSDK)) {
+    deleteDir(name);
+  }
+}
+
 // Extract the SDK version from the toolchain file and normalize it.
 function extractSDKVersion(toolchainFile) {
   if (!fs.existsSync(toolchainFile)) {
@@ -227,6 +243,8 @@ function ensureSDK() {
 
   deleteDir(SDKZip);
 
+  removeUnusedSDKs();
+
   return eventualVersionedPath;
 }