diff --git a/agent/src/main/java/com/microsoft/hydralab/agent/util/FileLoadUtil.java b/agent/src/main/java/com/microsoft/hydralab/agent/util/FileLoadUtil.java
index f6799e9fb..e4787c7e2 100644
--- a/agent/src/main/java/com/microsoft/hydralab/agent/util/FileLoadUtil.java
+++ b/agent/src/main/java/com/microsoft/hydralab/agent/util/FileLoadUtil.java
@@ -19,7 +19,6 @@
 
 import javax.annotation.Resource;
 import java.io.File;
-import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
@@ -88,14 +87,11 @@ public void loadAttachments(Task task) {
 
     public void installWinApp(StorageFileInfo attachment) {
         try {
-            Runtime runtime = Runtime.getRuntime();
             File attachmentFile = downloadFile(attachment, appOptions.getTestPackageLocation(), attachment.getBlobPath());
-            String installCommand = "& { Add-AppxPackage -ForceApplicationShutdown -forceupdatefromanyversion -Path '" +
-                    attachmentFile.getAbsolutePath() + "' }";
-            String[] command = new String[]{"Powershell.exe", "-Command", installCommand};
+            ProcessBuilder processBuilder = createWinAppInstallProcess(attachmentFile);
 
-            log.info("Install Win-App start command array: {}", Arrays.asList(command));
-            Process process = runtime.exec(command);
+            log.info("Install Win-App start command array: {}", processBuilder.command());
+            Process process = processBuilder.start();
             CommandOutputReceiver err = new CommandOutputReceiver(process.getErrorStream(), log);
             CommandOutputReceiver out = new CommandOutputReceiver(process.getInputStream(), log);
             err.start();
@@ -108,6 +104,15 @@ public void installWinApp(StorageFileInfo attachment) {
 
     }
 
+    static ProcessBuilder createWinAppInstallProcess(File attachmentFile) {
+        // Keep stored filenames out of PowerShell source; environment values are passed as data.
+        String installCommand = "& { Add-AppxPackage -ForceApplicationShutdown -forceupdatefromanyversion "
+                + "-Path $env:HYDRALAB_WIN_APP_PATH }";
+        ProcessBuilder processBuilder = new ProcessBuilder("Powershell.exe", "-Command", installCommand);
+        processBuilder.environment().put("HYDRALAB_WIN_APP_PATH", attachmentFile.getAbsolutePath());
+        return processBuilder;
+    }
+
     public void loadCommonFile(StorageFileInfo attachment, Task task) {
         try {
             File loadFolder = new File(task.getResourceDir(), attachment.getLoadDir());
diff --git a/agent/src/test/java/com/microsoft/hydralab/agent/util/FileLoadUtilTest.java b/agent/src/test/java/com/microsoft/hydralab/agent/util/FileLoadUtilTest.java
new file mode 100644
index 000000000..32079e0ef
--- /dev/null
+++ b/agent/src/test/java/com/microsoft/hydralab/agent/util/FileLoadUtilTest.java
@@ -0,0 +1,52 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+package com.microsoft.hydralab.agent.util;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.util.List;
+
+class FileLoadUtilTest {
+    @Test
+    void winAppPathsArePassedAsDataNotPowerShellCode() {
+        List<String> paths = List.of(
+                "packages\\normal.appxbundle",
+                "packages\\O'Brien.appxbundle",
+                "package folder\\my app.appxbundle",
+                "应用程序\\安装包.appxbundle",
+                "packages\\$env.appxbundle",
+                "packages\\`backtick`.appxbundle",
+                "packages\\semi;colon.appxbundle",
+                "packages\\repeated'''quotes.appxbundle",
+                "packages\\quote'; $unused = 'data'; '.appxbundle");
+        List<String> expectedCommand = List.of("Powershell.exe", "-Command",
+                "& { Add-AppxPackage -ForceApplicationShutdown -forceupdatefromanyversion "
+                        + "-Path $env:HYDRALAB_WIN_APP_PATH }");
+
+        for (String path : paths) {
+            File attachmentFile = new File(path);
+            ProcessBuilder processBuilder = FileLoadUtil.createWinAppInstallProcess(attachmentFile);
+
+            Assertions.assertEquals(expectedCommand, processBuilder.command(), path);
+            Assertions.assertEquals(attachmentFile.getAbsolutePath(),
+                    processBuilder.environment().get("HYDRALAB_WIN_APP_PATH"), path);
+        }
+    }
+
+    @Test
+    void winAppInstallPathsAreScopedToEachProcess() {
+        File firstFile = new File("packages\\first.appxbundle");
+        File secondFile = new File("packages\\second.appxbundle");
+        String parentPath = System.getenv("HYDRALAB_WIN_APP_PATH");
+
+        ProcessBuilder first = FileLoadUtil.createWinAppInstallProcess(firstFile);
+        ProcessBuilder second = FileLoadUtil.createWinAppInstallProcess(secondFile);
+
+        Assertions.assertEquals(firstFile.getAbsolutePath(), first.environment().get("HYDRALAB_WIN_APP_PATH"));
+        Assertions.assertEquals(secondFile.getAbsolutePath(), second.environment().get("HYDRALAB_WIN_APP_PATH"));
+        Assertions.assertEquals(parentPath, System.getenv("HYDRALAB_WIN_APP_PATH"));
+    }
+}