diff --git a/Sources/TSCBasic/Process.swift b/Sources/TSCBasic/Process.swift
index 1262b1ac..e13fd2de 100644
--- a/Sources/TSCBasic/Process.swift
+++ b/Sources/TSCBasic/Process.swift
@@ -351,35 +351,30 @@ public final class Process {
                 pathString: ProcessEnv.path,
                 currentWorkingDirectory: cwdOpt
             )
+            var searchPaths: [AbsolutePath] = []
 #if os(Windows)
-            var searchPaths = Array<AbsolutePath>()
             var buffer = Array<WCHAR>(repeating: 0, count: Int(MAX_PATH + 1))
-
             // The 32-bit Windows system directory
-            GetSystemDirectoryW(&buffer, .init(MAX_PATH + 1))
-            searchPaths.append(AbsolutePath(String(decodingCString: buffer, as: UTF16.self)))
-
+            if GetSystemDirectoryW(&buffer, .init(buffer.count)) > 0 {
+                searchPaths.append(AbsolutePath(String(decodingCString: buffer, as: UTF16.self)))
+            }
             // The 16-bit Windows system directory
             if let systemDrive = ProcessEnv.vars["systemdrive"],
                let systemPath = try? AbsolutePath(validating: "\(systemDrive))\\System") {
                 searchPaths.append(systemPath)
             }
-
             // The Windows directory
-            GetWindowsDirectoryW(&buffer, .init(MAX_PATH + 1))
-            searchPaths.append(AbsolutePath(String(decodingCString: buffer, as: UTF16.self)))
-
-            searchPaths.append(contentsOf: envSearchPaths)
-#else
-            let searchPaths = envSearchPaths
+            if GetWindowsDirectoryW(&buffer, .init(buffer.count)) > 0 {
+                searchPaths.append(AbsolutePath(String(decodingCString: buffer, as: UTF16.self)))
+            }
 #endif
+            searchPaths.append(contentsOf: envSearchPaths)
             // Lookup and cache the executable path.
             let value = lookupExecutablePath(
                 filename: program,
                 currentWorkingDirectory: cwdOpt,
                 searchPaths: searchPaths
             )
-            Process.validatedExecutablesMap[program] = value
             return value
         }
         // This should cover the most common cases, i.e. when the cache is most helpful.