diff --git a/lib/file/mkdir_other.go b/lib/file/mkdir_other.go
index 6baa7566b..3803885fb 100644
--- a/lib/file/mkdir_other.go
+++ b/lib/file/mkdir_other.go
@@ -1,10 +1,10 @@
-//go:build !windows
+//go:build !windows || go1.22
 
 package file
 
 import "os"
 
-// MkdirAll just calls os.MkdirAll on non-Windows.
+// MkdirAll just calls os.MkdirAll on non-Windows and with go1.22 or newer on Windows
 func MkdirAll(path string, perm os.FileMode) error {
 	return os.MkdirAll(path, perm)
 }
diff --git a/lib/file/mkdir_windows.go b/lib/file/mkdir_windows.go
index 4b5ba4f12..0da50c0c8 100644
--- a/lib/file/mkdir_windows.go
+++ b/lib/file/mkdir_windows.go
@@ -1,4 +1,4 @@
-//go:build windows
+//go:build windows && !go1.22
 
 package file
 
diff --git a/lib/file/mkdir_windows_go122_test.go b/lib/file/mkdir_windows_go122_test.go
new file mode 100644
index 000000000..eb9bbbef9
--- /dev/null
+++ b/lib/file/mkdir_windows_go122_test.go
@@ -0,0 +1,122 @@
+//go:build windows && go1.22
+
+package file
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func checkMkdirAll(t *testing.T, path string, valid bool, errormsgs ...string) {
+	if valid {
+		assert.NoError(t, os.MkdirAll(path, 0777))
+	} else {
+		err := os.MkdirAll(path, 0777)
+		assert.Error(t, err)
+		ok := false
+		for _, msg := range errormsgs {
+			if err.Error() == msg {
+				ok = true
+			}
+		}
+		assert.True(t, ok, fmt.Sprintf("Error message '%v' didn't match any of %v", err, errormsgs))
+	}
+}
+
+func checkMkdirAllSubdirs(t *testing.T, path string, valid bool, errormsgs ...string) {
+	checkMkdirAll(t, path, valid, errormsgs...)
+	checkMkdirAll(t, path+`\`, valid, errormsgs...)
+	checkMkdirAll(t, path+`\parent`, valid, errormsgs...)
+	checkMkdirAll(t, path+`\parent\`, valid, errormsgs...)
+	checkMkdirAll(t, path+`\parent\child`, valid, errormsgs...)
+	checkMkdirAll(t, path+`\parent\child\`, valid, errormsgs...)
+}
+
+// Testing paths on existing drive
+func TestMkdirAllOnDrive(t *testing.T) {
+	path := t.TempDir()
+
+	dir, err := os.Stat(path)
+	require.NoError(t, err)
+	require.True(t, dir.IsDir())
+
+	drive := filepath.VolumeName(path)
+
+	checkMkdirAll(t, drive, true, "")
+	checkMkdirAll(t, drive+`\`, true, "")
+	checkMkdirAll(t, `\\?\`+drive, false, fmt.Sprintf(`mkdir \\?\%s: Access is denied.`, drive)) // This isn't actually a valid Windows path, it worked under go1.21.3 but fails under go1.21.4 and newer
+	checkMkdirAll(t, `\\?\`+drive+`\`, true, "")
+	checkMkdirAllSubdirs(t, path, true, "")
+	checkMkdirAllSubdirs(t, `\\?\`+path, true, "")
+}
+
+// Testing paths on unused drive
+// This covers the cases that we wanted to improve with our own custom version
+// of golang's os.MkdirAll, introduced in PR #5401. Before go1.22 the original
+// os.MkdirAll would recurse extended-length paths down to the "\\?" prefix and
+// return the noninformative error:
+// "mkdir \\?: The filename, directory name, or volume label syntax is incorrect."
+// Our version stopped the recursion at drive's root directory, and reported,
+// before go1.21.4:
+// "mkdir \\?\A:\: The system cannot find the path specified."
+// or, starting with go1.21.4:
+// "mkdir \\?\A:: The system cannot find the path specified."
+// See https://github.com/rclone/rclone/pull/5401.
+// Starting with go1.22 golang's os.MkdirAll have similar improvements that made
+// our custom version no longer necessary.
+func TestMkdirAllOnUnusedDrive(t *testing.T) {
+	letter := FindUnusedDriveLetter()
+	require.NotEqual(t, letter, 0)
+	drive := string(letter) + ":"
+	checkMkdirAll(t, drive, false, fmt.Sprintf(`mkdir %s: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\`, false, fmt.Sprintf(`mkdir %s\: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\`, false, fmt.Sprintf(`mkdir %s\parent\: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\child`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\child\`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+
+	drive = `\\?\` + drive
+	checkMkdirAll(t, drive, false, fmt.Sprintf(`mkdir %s: The system cannot find the file specified.`, drive))
+	checkMkdirAll(t, drive+`\`, false, fmt.Sprintf(`mkdir %s\: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\`, false, fmt.Sprintf(`mkdir %s\parent\: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\child`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+	checkMkdirAll(t, drive+`\parent\child\`, false, fmt.Sprintf(`mkdir %s\parent: The system cannot find the path specified.`, drive))
+}
+
+// Testing paths on unknown network host
+// This covers more cases that we wanted to improve in our custom version of
+// golang's os.MkdirAll, extending that explained in TestMkdirAllOnUnusedDrive.
+// With our first fix, stopping it from recursing extended-length paths down to
+// the "\\?" prefix, it would now stop at `\\?\UNC`, because that is what
+// filepath.VolumeName returns (which is wrong, that is not a volume name!),
+// and still return a noninformative error:
+// "mkdir \\?\UNC\\: The filename, directory name, or volume label syntax is incorrect."
+// Our version stopped the recursion at level before this, and reports:
+// "mkdir \\?\UNC\0.0.0.0: The specified path is invalid."
+// See https://github.com/rclone/rclone/pull/6420.
+// Starting with go1.22 golang's os.MkdirAll have similar improvements that made
+// our custom version no longer necessary.
+func TestMkdirAllOnUnusedNetworkHost(t *testing.T) {
+	sharePath := `\\0.0.0.0\share`
+	checkMkdirAll(t, sharePath, false, fmt.Sprintf(`mkdir %s: The format of the specified network name is invalid.`, sharePath))
+	checkMkdirAll(t, sharePath+`\`, false, fmt.Sprintf(`mkdir %s\: The format of the specified network name is invalid.`, sharePath))
+	checkMkdirAll(t, sharePath+`\parent`, false, fmt.Sprintf(`mkdir %s\parent: The format of the specified network name is invalid.`, sharePath))
+	checkMkdirAll(t, sharePath+`\parent\`, false, fmt.Sprintf(`mkdir %s\parent\: The format of the specified network name is invalid.`, sharePath))
+	checkMkdirAll(t, sharePath+`\parent\child`, false, fmt.Sprintf(`mkdir %s\parent: The format of the specified network name is invalid.`, sharePath))
+	checkMkdirAll(t, sharePath+`\parent\child\`, false, fmt.Sprintf(`mkdir %s\parent: The format of the specified network name is invalid.`, sharePath))
+
+	serverPath := `\\?\UNC\0.0.0.0`
+	sharePath = serverPath + `\share`
+	checkMkdirAll(t, sharePath, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+	checkMkdirAll(t, sharePath+`\`, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+	checkMkdirAll(t, sharePath+`\parent`, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+	checkMkdirAll(t, sharePath+`\parent\`, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+	checkMkdirAll(t, sharePath+`\parent\child`, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+	checkMkdirAll(t, sharePath+`\parent\child\`, false, fmt.Sprintf(`mkdir %s: The specified path is invalid.`, serverPath))
+}
diff --git a/lib/file/mkdir_windows_test.go b/lib/file/mkdir_windows_test.go
index 75e050bf7..e6d4bd389 100644
--- a/lib/file/mkdir_windows_test.go
+++ b/lib/file/mkdir_windows_test.go
@@ -1,4 +1,4 @@
-//go:build windows
+//go:build windows && !go1.22
 
 package file