Modern developer tools are storage monsters.
If you use tools like:
- Cursor
- VS Code
- Docker
- Node.js
- AI/ML frameworks
- Electron apps
- Local LLM tools
- Low storage SSD system
- OR Any general apps
…you’ve probably noticed your C: drive slowly dying.
Even when apps are installed on another SSD, Windows still stores huge amounts of cache and configuration data inside:
C:\Users\<user>\AppData
Over time this becomes a problem:
- SSD fills up
- Windows updates fail
- Performance degrades
- AI model caches explode
- Docker eats tens of GB
- Electron apps duplicate Chromium storage everywhere
I got tired of manually moving folders and creating symlinks.
So I built a safer automated PowerShell migration utility.
What This Tool Does
The utility safely moves heavy AppData folders from C: to another drive and replaces them with NTFS junctions.
Applications continue working normally.
Windows still thinks the folders exist on C:.
But the actual data lives elsewhere.
Example
Before:
C:\Users\prath\AppData\Local\Cursor
After:
C:\Users\prath\AppData\Local\Cursor
-> D:\APPDATA_REDIRECT\Cursor\Local\Cursor
To the app:
- nothing changed
To your SSD:
- huge storage recovered
Why NTFS Junctions?
NTFS junctions are filesystem-level redirects built into Windows.
They are:
- fast
- transparent
- stable
- compatible with most Windows applications
Unlike shortcuts, applications treat junctions as real folders.
This makes them perfect for:
- caches
- package managers
- AI model storage
- extension folders
- Electron app data
- Docker layers
Features
Safe Migration Workflow
The script:
- scans folders
- verifies paths
- creates migration snapshots
- transfers data
- creates junctions
- validates success
- rolls back automatically on failure
Detects Existing Migrations
Already migrated folders are detected automatically:
[ALREADY MIGRATED]
[-] [Roaming]
C:\Users\prath\AppData\Roaming\Cursor
-> D:\APPDATA_REDIRECT\Cursor\Roaming\Cursor
No duplicate work.
No accidental corruption.
Interactive Folder Selection
You choose exactly what gets migrated:
[1] [Local]
C:\Users\prath\AppData\Local\Cursor
[2] [Roaming]
C:\Users\prath\AppData\Roaming\Cursor
Supports:
- single selection
- multiple selection
- migrate all
Uses robocopy
Instead of basic file copy operations, the tool uses:
robocopy /E /MOVE
Why this matters:
- resilient transfers
- retries
- metadata preservation
- large-folder reliability
- safer than naive copy/delete
Automatic Rollback System
If anything fails:
- junction creation
- move operation
- verification
…the script automatically restores the original folder.
This is critical when dealing with live application data.
Best Use Cases
This is especially useful for developers and AI engineers.
Cursor / VS Code
Extensions and AI indexes become massive over time.
Move:
AppData\Roaming\Cursor
AppData\Local\Cursor
Docker
Docker Desktop can consume absurd amounts of SSD space.
Move:
AppData\Local\Docker
Node.js
Package managers and caches grow endlessly.
Useful targets:
npm-cache
pnpm-store
yarn cache
AI & ML Tools
Perfect for:
- model downloads
- embeddings
- vector indexes
- Hugging Face cache
- Ollama storage
- CUDA caches
How the Script Works
The workflow is designed to be defensive and recoverable.
Step 1 — Scan
The script searches:
AppData\Local
AppData\Roaming
AppData\LocalLow
and even:
C:\Users\<user>\.<app>
Step 2 — Snapshot
Before migration it records:
- file count
- destination
- size
- state
This enables recovery logic later.
Step 3 — Move Files
Using:
robocopy /MOVE
The original directory is removed only after successful transfer.
Step 4 — Create Junction
PowerShell creates:
New-Item -ItemType Junction
Applications continue working normally.
Step 5 — Verification
The script checks:
- junction exists
- target exists
- transfer succeeded
If validation fails:
- rollback begins automatically
Example Migration Output
==================================================
STARTING MIGRATION
==================================================
Migrating:
C:\Users\prath\AppData\Local\Cursor
[+] Files moved successfully
[+] Junction created
C:\Users\prath\AppData\Local\Cursor
->
D:\APPDATA_REDIRECT\Cursor\Local\Cursor
Safety Notes
Do NOT migrate:
- Windows system folders
- Microsoft core directories
- active system temp folders
- random unknown services
Always:
- close applications first
- stop Docker if migrating Docker
- stop AI servers before migration
- run PowerShell as Administrator
The script already blocks some dangerous paths automatically.
Requirements
- Windows
- NTFS filesystem
- PowerShell
- Administrator privileges
Usage
Run PowerShell as Administrator:
powershell -ExecutionPolicy Bypass -File migration.ps1
Real-World Impact
On my system this recovered:
- tens of GB from Cursor
- massive Docker cache usage
- AI model storage clutter
- Electron app duplication
Without breaking a single app.
This approach is especially useful on:
- laptops with small SSDs
- dev machines
- AI workstations
- dual-drive setups
- systems using local LLMs
Final Thoughts
Windows AppData management becomes painful once you start working with modern development and AI tooling.
The problem isn’t installation size anymore.
It’s hidden storage growth.
NTFS junctions are one of the cleanest solutions available on Windows, and automating the process safely makes a huge difference.
If you’re constantly fighting low SSD space while doing development, AI, or Docker work — this approach can save your setup.
GitHub Gist Structure
migration.ps1
README.md
Windows AppData Junction Migrator Gist 🔗
License
MIT License