diff --git a/lib/index.js b/lib/index.js
index 1d42204..571ff6b 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -131,7 +131,7 @@ const open = (_args, opts = {}, extra = {}) => {
   let platform = process.platform
   // process.platform === 'linux' may actually indicate WSL, if that's the case
   // we want to treat things as win32 anyway so the host can open the argument
-  if (platform === 'linux' && os.release().includes('Microsoft')) {
+  if (platform === 'linux' && os.release().toLowerCase().includes('microsoft')) {
     platform = 'win32'
   }
 
diff --git a/test/open.js b/test/open.js
index dfa16a8..674e721 100644
--- a/test/open.js
+++ b/test/open.js
@@ -180,6 +180,32 @@ t.test('process.platform === linux', (t) => {
     t.ok(proc.called)
   })
 
+  t.test('when os.release() includes microsoft treats as win32', async (t) => {
+    const comSpec = process.env.ComSpec
+    process.env.ComSpec = 'C:\\Windows\\System32\\cmd.exe'
+    t.teardown(() => {
+      process.env.ComSPec = comSpec
+    })
+
+    const promiseSpawnMock = t.mock('../lib/index.js', {
+      os: {
+        release: () => 'microsoft',
+      },
+    })
+
+    const proc = spawk.spawn('C:\\Windows\\System32\\cmd.exe',
+      ['/d', '/s', '/c', 'start "" https://google.com'],
+      { shell: false })
+
+    const result = await promiseSpawnMock.open('https://google.com')
+    t.hasStrict(result, {
+      code: 0,
+      signal: undefined,
+    })
+
+    t.ok(proc.called)
+  })
+
   t.end()
 })