diff --git a/GraphcodeKit/Sources/Sessions/ZmxLocator.swift b/GraphcodeKit/Sources/Sessions/ZmxLocator.swift
index 7df5906e..af8d6427 100644
--- a/GraphcodeKit/Sources/Sessions/ZmxLocator.swift
+++ b/GraphcodeKit/Sources/Sessions/ZmxLocator.swift
@@ -7,7 +7,12 @@ import Foundation
 public enum ZmxLocator {
   public static var binaryURL: URL {
     #if os(Windows)
-      SupportDirectory.binDirectory.appendingPathComponent("zmx.exe")
+      resolve(
+        candidates(
+          executableDirectory: Bundle.main.executableURL?.deletingLastPathComponent(),
+          supportBinDirectory: SupportDirectory.binDirectory,
+          executableName: "zmx.exe"),
+        isExecutable: FileManager.default.isExecutableFile(atPath:))
     #else
       SupportDirectory.binDirectory.appendingPathComponent("zmx")
     #endif
@@ -16,4 +21,20 @@ public enum ZmxLocator {
   public static var isInstalled: Bool {
     FileManager.default.isExecutableFile(atPath: binaryURL.path)
   }
+
+  /// The places `zmx` may live, most preferred first; the last is the support directory's
+  /// `bin`, which is also what is reported when none of them exists. The Windows package
+  /// installs `zmx.exe` beside `graphcoded.exe` and never copies it into the support
+  /// directory, so the running executable's own directory comes first.
+  static func candidates(
+    executableDirectory: URL?, supportBinDirectory: URL, executableName: String
+  ) -> [URL] {
+    let supportBinary = supportBinDirectory.appendingPathComponent(executableName)
+    guard let executableDirectory else { return [supportBinary] }
+    return [executableDirectory.appendingPathComponent(executableName), supportBinary]
+  }
+
+  static func resolve(_ candidates: [URL], isExecutable: (String) -> Bool) -> URL {
+    candidates.first { isExecutable($0.path) } ?? candidates[candidates.count - 1]
+  }
 }
diff --git a/graphcode/Tests/SupportDirectoryTests.swift b/graphcode/Tests/SupportDirectoryTests.swift
index e0134ec5..c504c49f 100644
--- a/graphcode/Tests/SupportDirectoryTests.swift
+++ b/graphcode/Tests/SupportDirectoryTests.swift
@@ -26,6 +26,26 @@ struct SupportDirectoryTests {
     #expect(SupportDirectory.binDirectory.deletingLastPathComponent() == root)
   }
 
+  @Test
+  func zmxResolutionPrefersAnExecutableSiblingThenTheSupportBin() {
+    // Windows packages zmx.exe beside graphcoded; macOS keeps using the support bin, and
+    // `binaryURL` there is unchanged (asserted above).
+    let install = URL(fileURLWithPath: "/opt/graphcode/bin", isDirectory: true)
+    let support = SupportDirectory.binDirectory
+    let candidates = ZmxLocator.candidates(
+      executableDirectory: install, supportBinDirectory: support, executableName: "zmx")
+    let sibling = install.appendingPathComponent("zmx")
+    let supportZmx = support.appendingPathComponent("zmx")
+
+    #expect(candidates == [sibling, supportZmx])
+    #expect(ZmxLocator.resolve(candidates) { $0 == sibling.path } == sibling)
+    #expect(ZmxLocator.resolve(candidates) { $0 == supportZmx.path } == supportZmx)
+    #expect(ZmxLocator.resolve(candidates) { _ in false } == supportZmx)
+    #if !os(Windows)
+      #expect(ZmxLocator.binaryURL == supportZmx)
+    #endif
+  }
+
   @Test
   func aBackslashOverrideRemainsRelativeOnDarwin() {
     let home = URL(fileURLWithPath: "/Users/test-user", isDirectory: true)
diff --git a/windows-tests/WindowsDaemonTests.swift b/windows-tests/WindowsDaemonTests.swift
index 7f60ff1f..572a9ca9 100644
--- a/windows-tests/WindowsDaemonTests.swift
+++ b/windows-tests/WindowsDaemonTests.swift
@@ -41,6 +41,34 @@ final class WindowsDaemonTests: XCTestCase {
       XCTAssertEqual(ZmxLocator.binaryURL.lastPathComponent, "zmx.exe")
     }
 
+    // The packaged daemon ships zmx.exe beside itself under %LOCALAPPDATA%\GraphCode;
+    // nothing copies it into the support directory, so the support bin alone left the
+    // daemon unable to launch, message or kill any loop session (beta9 Dev Box).
+    func testZmxLocatorPrefersThePackagedSiblingOfTheRunningExecutable() {
+      let install = URL(fileURLWithPath: #"C:\Users\u\AppData\Local\GraphCode\current\bin"#)
+      let support = URL(fileURLWithPath: #"C:\Users\u\.graphcode\bin"#)
+      let candidates = ZmxLocator.candidates(
+        executableDirectory: install, supportBinDirectory: support, executableName: "zmx.exe")
+      let sibling = install.appendingPathComponent("zmx.exe")
+      let supportZmx = support.appendingPathComponent("zmx.exe")
+
+      XCTAssertEqual(candidates, [sibling, supportZmx])
+      XCTAssertEqual(ZmxLocator.resolve(candidates) { $0 == sibling.path }, sibling)
+      XCTAssertEqual(
+        ZmxLocator.resolve(candidates) { [sibling.path, supportZmx.path].contains($0) }, sibling)
+      XCTAssertEqual(ZmxLocator.resolve(candidates) { $0 == supportZmx.path }, supportZmx)
+      // Neither present: report the support bin, so isInstalled stays false.
+      XCTAssertEqual(ZmxLocator.resolve(candidates) { _ in false }, supportZmx)
+    }
+
+    func testZmxLocatorWithoutAnExecutableDirectoryUsesTheSupportBin() {
+      let support = URL(fileURLWithPath: #"C:\Users\u\.graphcode\bin"#)
+      XCTAssertEqual(
+        ZmxLocator.candidates(
+          executableDirectory: nil, supportBinDirectory: support, executableName: "zmx.exe"),
+        [support.appendingPathComponent("zmx.exe")])
+    }
+
     func testWindowsProviderProbeUsesWhere() {
       let invocation = ProviderPath.probeInvocation(for: "copilot")
       XCTAssertEqual(URL(fileURLWithPath: invocation[0]).lastPathComponent, "where.exe")