diff --git a/install.ps1 b/install.ps1
index 08acf45..f6c05ca 100644
--- a/install.ps1
+++ b/install.ps1
@@ -303,6 +303,23 @@ function Normalize-PathForCompare($Path) {
     )
 }
 
+function PathList-Contains($PathValue, $PathToFind) {
+    if (-not $PathValue) {
+        return $false
+    }
+    $wanted = Normalize-PathForCompare $PathToFind
+    foreach ($entry in ($PathValue -split ';' | Where-Object { $_ })) {
+        try {
+            if ((Normalize-PathForCompare $entry) -ieq $wanted) {
+                return $true
+            }
+        }
+        catch {
+        }
+    }
+    return $false
+}
+
 function Assert-NoRelativePathSegments($Path) {
     foreach ($segment in ($Path -split '[\\/]')) {
         if ($segment -eq "." -or $segment -eq "..") {
@@ -339,7 +356,7 @@ function Add-UserPath($PathToAdd) {
         $entries = @($userPath -split ';' | Where-Object { $_ })
     }
     $wanted = Normalize-PathForCompare $PathToAdd
-    if (-not (";$env:Path;").Contains(";$PathToAdd;")) {
+    if (-not (PathList-Contains $env:Path $PathToAdd)) {
         $env:Path = "$PathToAdd;$env:Path"
     }
     foreach ($entry in $entries) {
diff --git a/tests/release_scripts.rs b/tests/release_scripts.rs
index 9d7216b..bd66142 100644
--- a/tests/release_scripts.rs
+++ b/tests/release_scripts.rs
@@ -276,14 +276,16 @@ fn windows_prebuilt_install_requires_client_but_not_bench() {
 fn windows_installer_adds_user_path_idempotently() {
     let ps1 = include_str!("../install.ps1");
     assert!(ps1.contains("function Add-UserPath($PathToAdd)"));
+    assert!(ps1.contains("function PathList-Contains($PathValue, $PathToFind)"));
+    assert!(ps1.contains("$wanted = Normalize-PathForCompare $PathToFind"));
+    assert!(ps1.contains("foreach ($entry in ($PathValue -split ';' | Where-Object { $_ }))"));
     assert!(ps1.contains("$wanted = Normalize-PathForCompare $PathToAdd"));
     assert!(ps1.contains("-ieq $wanted"));
     assert!(ps1.contains("(@($entries) + $PathToAdd) -join ';'"));
-    assert!(ps1.contains("(\";$env:Path;\").Contains(\";$PathToAdd;\")"));
+    assert!(ps1.contains("PathList-Contains $env:Path $PathToAdd"));
     assert!(ps1.contains("$env:Path = \"$PathToAdd;$env:Path\""));
     assert!(
-        ps1.find("(\";$env:Path;\").Contains(\";$PathToAdd;\")")
-            .unwrap()
+        ps1.find("PathList-Contains $env:Path $PathToAdd").unwrap()
             < ps1.find("foreach ($entry in $entries)").unwrap(),
         "Windows installer must refresh the current shell PATH even when user PATH already contains Dosh"
     );