PowerShell · adityapatwardhan · May 15, 2026 · Oct 22, 2025
diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/ConsoleHost.cs
@@ -141,13 +141,16 @@ internal static int Start(
             try
             {
                 string profileDir = Platform.CacheDirectory;
-#if !UNIX
-                if (!Directory.Exists(profileDir))
+                if (!string.IsNullOrEmpty(profileDir))
                 {
-                    Directory.CreateDirectory(profileDir);
-                }
+#if !UNIX
+                    if (!Directory.Exists(profileDir))
+                    {
+                        Directory.CreateDirectory(profileDir);
+                    }
 #endif
-                ProfileOptimization.SetProfileRoot(profileDir);
+                    ProfileOptimization.SetProfileRoot(profileDir);
+                }
             }
             catch
             {

diff --git a/src/Microsoft.PowerShell.ConsoleHost/host/msh/UpdatesNotification.cs b/src/Microsoft.PowerShell.ConsoleHost/host/msh/UpdatesNotification.cs
@@ -60,12 +60,12 @@ internal static class UpdatesNotification
         static UpdatesNotification()
         {
             s_notificationType = GetNotificationType();
-            CanNotifyUpdates = s_notificationType != NotificationType.Off;
+            CanNotifyUpdates = s_notificationType != NotificationType.Off
+                && Platform.TryDeriveFromCache(PSVersionInfo.GitCommitId, out s_cacheDirectory);
 
             if (CanNotifyUpdates)
             {
                 s_enumOptions = new EnumerationOptions();
-                s_cacheDirectory = Path.Combine(Platform.CacheDirectory, PSVersionInfo.GitCommitId);
 
                 // Build the template/pattern strings for the configured notification type.
                 string typeNum = ((int)s_notificationType).ToString();

diff --git a/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs b/src/System.Management.Automation/CoreCLR/CorePsPlatform.cs
@@ -167,8 +167,13 @@ public static bool IsStaSupported
         internal static readonly string ConfigDirectory = Platform.SelectProductNameForDirectory(Platform.XDG_Type.CONFIG);
 #else
         // Gets the location for cache and config folders.
-        internal static readonly string CacheDirectory = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData) + @"\Microsoft\PowerShell";
-        internal static readonly string ConfigDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Personal) + @"\PowerShell";
+        internal static readonly string CacheDirectory = SafeDeriveFromSpecialFolder(
+            Environment.SpecialFolder.LocalApplicationData,
+            @"Microsoft\PowerShell");
+
+        internal static readonly string ConfigDirectory = SafeDeriveFromSpecialFolder(
+            Environment.SpecialFolder.Personal,
+            @"PowerShell");
 
         private static readonly Lazy<bool> _isStaSupported = new Lazy<bool>(() =>
         {
@@ -189,6 +194,30 @@ public static bool IsStaSupported
         private static bool? _isWindowsDesktop = null;
 #endif
 
+        internal static bool TryDeriveFromCache(string path1, out string result)
+        {
+            if (CacheDirectory is null or [])
+            {
+                result = null;
+                return false;
+            }
+
+            result = Path.Combine(CacheDirectory, path1);
+            return true;
+        }
+
+        internal static bool TryDeriveFromCache(string path1, string path2, out string result)
+        {
+            if (CacheDirectory is null or [])
+            {
+                result = null;
+                return false;
+            }
+
+            result = Path.Combine(CacheDirectory, path1, path2);
+            return true;
+        }
+
         // format files
         internal static readonly string[] FormatFileNames = new string[]
         {
@@ -218,6 +247,17 @@ internal static class CommonEnvVariableNames
 #endif
         }
 
+        private static string SafeDeriveFromSpecialFolder(Environment.SpecialFolder specialFolder, string subPath)
+        {
+            string basePath = Environment.GetFolderPath(specialFolder, Environment.SpecialFolderOption.DoNotVerify);
+            if (string.IsNullOrWhiteSpace(basePath))
+            {
+                return string.Empty;
+            }
+
+            return Path.Join(basePath, subPath);
+        }
+
 #if UNIX
         private static string s_tempHome = null;
 
@@ -360,7 +400,7 @@ internal static string GetFolderPath(Environment.SpecialFolder folder)
                 _ => throw new NotSupportedException()
             };
 #else
-            return Environment.GetFolderPath(folder);
+            return Environment.GetFolderPath(folder, Environment.SpecialFolderOption.DoNotVerify);
 #endif
         }
 

diff --git a/src/System.Management.Automation/engine/CommandDiscovery.cs b/src/System.Management.Automation/engine/CommandDiscovery.cs
@@ -1221,11 +1221,17 @@ internal LookupPathCollection GetLookupDirectoryPaths()
                         string tempDir = directory.TrimStart();
                         if (tempDir.EqualsOrdinalIgnoreCase("~"))
                         {
-                            tempDir = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+                            tempDir = Environment.GetFolderPath(
+                                Environment.SpecialFolder.UserProfile,
+                                Environment.SpecialFolderOption.DoNotVerify);
                         }
                         else if (tempDir.StartsWith("~" + Path.DirectorySeparatorChar))
                         {
-                            tempDir = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) + Path.DirectorySeparatorChar + tempDir.Substring(2);
+                            tempDir = Environment.GetFolderPath(
+                                Environment.SpecialFolder.UserProfile,
+                                Environment.SpecialFolderOption.DoNotVerify)
+                                + Path.DirectorySeparatorChar
+                                + tempDir.Substring(2);
                         }
 
                         _cachedPath.Add(tempDir);

diff --git a/src/System.Management.Automation/engine/Modules/AnalysisCache.cs b/src/System.Management.Automation/engine/Modules/AnalysisCache.cs
@@ -664,6 +664,11 @@ private static byte[] GetHeader()
 
         public void QueueSerialization()
         {
+            if (string.IsNullOrEmpty(s_cacheStoreLocation))
+            {
+                return;
+            }
+
             // We expect many modules to rapidly call for serialization.
             // Instead of doing it right away, we'll queue a task that starts writing
             // after it seems like we've stopped adding stuff to write out.  This is
@@ -1121,7 +1126,7 @@ static AnalysisCacheData()
                 cacheFileName = string.Create(CultureInfo.InvariantCulture, $"{cacheFileName}-{hashString}");
             }
 
-            s_cacheStoreLocation = Path.Combine(Platform.CacheDirectory, cacheFileName);
+            Platform.TryDeriveFromCache(cacheFileName, out s_cacheStoreLocation);
         }
     }
 

diff --git a/src/System.Management.Automation/engine/PSConfiguration.cs b/src/System.Management.Automation/engine/PSConfiguration.cs
@@ -89,7 +89,10 @@ private PowerShellConfig()
             // Note: This directory may or may not exist depending upon the execution scenario.
             // Writes will attempt to create the directory if it does not already exist.
             perUserConfigDirectory = Platform.ConfigDirectory;
-            perUserConfigFile = Path.Combine(perUserConfigDirectory, ConfigFileName);
+            if (!string.IsNullOrEmpty(perUserConfigDirectory))
+            {
+                perUserConfigFile = Path.Combine(perUserConfigDirectory, ConfigFileName);
+            }
 
             emptyConfig = new JObject();
             configRoots = new JObject[2];
@@ -387,6 +390,11 @@ internal PSKeyword GetLogKeywords()
         private T ReadValueFromFile<T>(ConfigScope scope, string key, T defaultValue = default)
         {
             string fileName = GetConfigFilePath(scope);
+            if (string.IsNullOrEmpty(fileName))
+            {
+                return defaultValue;
+            }
+
             JObject configData = configRoots[(int)scope];
 
             if (configData == null)

diff --git a/src/System.Management.Automation/engine/hostifaces/HostUtilities.cs b/src/System.Management.Automation/engine/hostifaces/HostUtilities.cs
@@ -230,10 +230,11 @@ internal static string GetFullProfileFileName(string shellId, bool forCurrentUse
             else
             {
                 basePath = GetAllUsersFolderPath(shellId);
-                if (string.IsNullOrEmpty(basePath))
-                {
-                    return string.Empty;
-                }
+            }
+
+            if (string.IsNullOrEmpty(basePath))
+            {
+                return string.Empty;
             }
 
             string profileName = useTestProfile ? "profile_test.ps1" : "profile.ps1";

diff --git a/src/System.Management.Automation/engine/hostifaces/MshHostUserInterface.cs b/src/System.Management.Automation/engine/hostifaces/MshHostUserInterface.cs
@@ -1156,6 +1156,11 @@ internal static string GetTranscriptPath(string baseDirectory, bool includeDate)
                 }
             }
 
+            if (string.IsNullOrEmpty(baseDirectory))
+            {
+                return string.Empty;
+            }
+
             if (includeDate)
             {
                 baseDirectory = Path.Combine(baseDirectory, DateTime.Now.ToString("yyyyMMdd", CultureInfo.InvariantCulture));