Persisting subst Mappings

How-To: Persist a subst Drive Mapping

This is part 3 of the subst series. For the background on why a short drive letter helps and how to create the mapping, see 02_solution_subst.

Problem

A subst mapping disappears at reboot, so the short drive letter has to be recreated by hand each session.

Create the Mapping

subst E: D:\eCode

Remove the Mapping

subst E: /d

Fix: Persist Across Reboots

Option A: Startup Script

Create a file such as subst-ecode.cmd:

@echo off
subst E: D:\eCode

Place it in the per-user Startup folder. Open it by pressing Win+R and running:

shell:startup

Option B: Task Scheduler

Create a task that runs at logon. From a command prompt:

schtasks /Create /TN "SubstECode" /SC ONLOGON /TR "cmd.exe /c subst E: D:\eCode"

Or in the Task Scheduler GUI: Create Basic Task, set the trigger to “When I log on”, the action to “Start a program”, the program to cmd.exe, and the arguments to /c subst E: D:\eCode.

To remove the task later:

schtasks /Delete /TN "SubstECode" /F

Why

subst mappings live only in the current logon session, so they must be recreated each time you sign in. Either option reruns the same command at logon.