DriveMapper

A small Windows command-line utility that maps local drive letters to network shares (or local paths) using subst.exe and assigns them friendly labels via the registry. Built primarily so Adobe Lightroom can find catalog folders behind a stable drive letter even when the underlying network path changes.

Why?

Lightroom binds catalogs and previews to drive letters. A regular Windows mapped network drive (net use) is not always treated identically to a local drive by every application. subst produces what looks like a local drive — which Lightroom is happy with — and DriveMapper automates creating those substitutions on every login, optionally waiting for the file server to be reachable first.

How it works

For every entry in DriveMappings.xml the tool:

1. If the path is a UNC path (\\server\share), pings the host until it replies (up to ~4 minutes) so it works even when started before the network is fully up.
2. Runs subst <Drive> <NetworkPath> to create the drive letter.
3. Writes the configured label into HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2\...\_LabelFromReg so Explorer shows a friendly name.

Installation

Option 1 — Download a release (recommended)

1. Grab the latest FL.DriveMapper-<version>-win-x64.zip from the Releases page (use win-arm64 on ARM machines).
2. Extract it somewhere stable, e.g. C:\Tools\DriveMapper\.
3. Edit DriveMappings.xml to match your shares (see below).
4. Register it to run at logon — see Run at logon below.

The published binary is self-contained: no .NET runtime install required.

Option 2 — Build from source

Requirements: .NET 10 SDK.

dotnet publish FL.DriveMapper/FL.DriveMapper.csproj -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true -o publish

The resulting publish/FL.DriveMapper.exe is a single self-contained executable.

Configuration

DriveMappings.xml lives next to the executable. Example:

<?xml version="1.0" encoding="utf-8" ?>
<DriveMappings>
  <Mappings>
    <DriveMapInfo>
      <Drive>L:</Drive>
      <NetworkPath>\\sepp\projekte</NetworkPath>
      <Label>Projekte Lightroom</Label>
    </DriveMapInfo>
    <DriveMapInfo>
      <Drive>M:</Drive>
      <NetworkPath>\\sepp\medien</NetworkPath>
      <Label>Medien</Label>
    </DriveMapInfo>
  </Mappings>
</DriveMappings>

Field	Meaning
Drive	The drive letter to create, e.g. L:
NetworkPath	The target — either a UNC path or a local folder
Label	The display name shown in Explorer for the mapped drive

Run at logon

A ready-to-import Windows Task Scheduler definition is shipped as TaskSchedulerSetting.xml.

1. Open Task Scheduler → Import Task...
2. Select TaskSchedulerSetting.xml.
3. Adjust the Action → Program/script path to point at your FL.DriveMapper.exe.
4. On the General tab, change User to your own account.

The task triggers at logon and runs with least-privilege; no admin rights are needed since subst and the relevant registry keys are per-user.

Logs

log4net is used for diagnostics. Drop a log4net.config file next to the executable and configure appenders as you like; without it the tool runs silently.

Releases & versioning

Pushing a tag vX.Y.Z to master triggers the Release workflow which builds self-contained single-file executables for win-x64, win-x86, and win-arm64 and publishes a GitHub Release with one zip per architecture.

Contributing

Dependencies are kept current automatically via Dependabot. Minor and patch NuGet updates as well as GitHub Actions updates are auto-merged once CI passes; major upgrades are opened as PRs for review.

License

MIT — see LICENSE.