PersistentSD

Keep your chosen drive letter assigned to the storage device you want.

A lightweight Windows utility that configures a preferred drive letter for a selected storage device and attempts to maintain that assignment at startup.

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Important

Drive-letter safety: If another partition already owns the preferred letter, PersistentSD logs the conflict and leaves that partition and its drive letter untouched. It does not forcibly take the letter away. Double-check the selected disk and preferred letter before installing.

Warning

Runtime validation is incomplete. Automated checks confirm PowerShell syntax, C# compilation, and ZIP packaging. They do not prove that installation, startup, reconnect handling, or real drive-letter assignment works correctly on every Windows system. Review Testing status before relying on the utility.

What PersistentSD does

PersistentSD provides a Windows Forms interface for selecting a storage disk and preferred drive letter. It saves your configuration and creates a PowerShell script launched by a scheduled task at startup under the SYSTEM account.

The generated script identifies the selected device using its Windows disk UniqueId, rather than relying only on its current drive letter. The manager can install or update the task, inspect basic task status, open Task Scheduler, and remove the task.

Features

• Select a storage device from the detected Windows disks.
• Choose a preferred drive letter from D: through Z:.
• Configure startup handling with a scheduled task running as SYSTEM.
• Inspect task status and check whether the configured script path can be resolved. This is not a complete runtime health check.
• Manage the scheduled task from the application.
• Retain recovery evidence through backups of replaced scripts/task XML and runtime logs.

Download and install

1. Open the latest PersistentSD release.
2. Download PersistentSD-v1.1.zip (or the ZIP attached to the version you intend to use).
3. Extract the ZIP into a folder you can keep in place.
4. Keep PersistentSD.exe and PersistentSD.ps1 together in that folder.
5. Run PersistentSD.exe as Administrator and read each confirmation prompt carefully.

The release ZIP includes the application, PowerShell template, README, and license. You do not need to download the EXE or script separately. Do not move or delete the script after installing the task unless you update or remove the task first.

Build from source

Requirements: Windows and the .NET Framework C# compiler (csc.exe).

1. Clone or download this repository.
2. Keep PersistentSD.ps1 beside the source and build files.
3. Run Build-PersistentSD.bat on Windows.
4. After a successful build, launch PersistentSD.exe as Administrator.

The build script searches standard 64-bit and 32-bit .NET Framework compiler locations. GitHub Actions also compiles and packages the app, but that automated build does not exercise actual storage changes.

How to use it

1. Open PersistentSD as Administrator.
2. Refresh the device list and select the intended storage device.
3. Select a preferred drive letter from D: through Z:.
4. Choose one of the offered script folders.
5. Select Save / Install / Update and review the confirmation prompts.
6. Use Check Status to inspect the registered task and its configured script path.
7. Open Task Scheduler from the app if you want to inspect the task directly.

Safety and behavior

Area	What to know
Device matching	The script matches the selected disk using its Windows UniqueId. If it cannot find exactly one matching disk, it should make no drive-letter changes.
Partition selection	System, boot, recovery, and certain reserved partition types are intended to be excluded. Among eligible data partitions, the script prefers one already using the selected letter, then one with an existing drive letter, then the first eligible partition.
Protected partitions	Protected-partition handling is intended as a safeguard, not a substitute for validating unusual disk layouts.
Letter conflicts	If another partition owns the preferred letter, the script leaves that volume untouched and retries later; it does not remove the other partition's letter.
Backups	Existing target scripts and scheduled-task XML are backed up before replacement when the manager can identify and read them. Backups are recovery copies, not an automatic rollback mechanism.
Failed updates	If task registration fails, the manager attempts to restore the previous script or remove a newly created script and does not save new preferences. Recovery itself can fail. If registration succeeds but later verification or preference saving fails, inspect the warning, Task Scheduler, script path, and backups manually.
Old files	Previous scripts are not automatically deleted. Verify the new setup before manually removing old copies.
Disk state	The script does not automatically bring an offline disk online or clear its read-only flag.
Logging	Runtime activity is written to PersistentSD.log beside the generated script, if that folder is writable.

Preferences are stored at %LOCALAPPDATA%\PersistentSD\preferences.txt. The startup task runs as SYSTEM, so the generated script must remain at the registered path and be accessible to that account. The task uses the selected device ID and drive letter embedded in the generated script; the user-profile preferences file is not the runtime task's source of truth.

Testing status

The automated workflow checks PowerShell template syntax, compiles the C# application, and creates a ZIP. It does not launch the GUI, install/remove a task, or validate actual drive-letter assignment, startup behavior, or device reconnects.

Those behaviors remain unverified until tested on Windows using the exact release ZIP. Follow the manual Windows test plan, record skipped or failed checks, and do not treat a successful build as proof of runtime correctness.

Project files

File	Purpose
PersistentSDManager.cs	Windows Forms interface and scheduled-task management
Build-PersistentSD.bat	Builds the Windows application
PersistentSDManager.exe.manifest	Requests administrator privileges
RazorBlade.ico	Application icon
PersistentSD.ps1	PowerShell runtime script template
PersistentSD.png	Application screenshot shown above
TESTING.md	Manual Windows validation checklist
LICENSE	MIT license

Feedback

Found a bug or have a suggestion? Open an issue on GitHub.

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PersistentSD — a small utility for keeping storage paths predictable.