How to Search a Disconnected Hard Drive on Mac
Arun Gopidas
You need a file from an old project. You're fairly sure it's on one of your external drives — the one from two years ago, maybe the older backup drive. Neither is plugged in right now. Spotlight shows nothing. Finder shows nothing. Your only option, with every other tool, is to go find the drive, plug it in, wait for it to mount, and search.
That's the standard approach. reverscan offers a different one: your drives stay searchable even when they're unplugged.
Why Disconnected Drives Disappear from Standard Search
Every file search tool on macOS — Spotlight, Finder, HoudahSpot, Alfred — relies on the drive being mounted. When a drive is connected, macOS assigns it a path (usually /Volumes/DriveName/), and files on it become accessible. When you unplug the drive, that path disappears. Files on it are invisible to every search tool until you reconnect.
This is a fundamental constraint of how macOS handles storage. It's not a bug — it's how the system works. A search tool that queries the live filesystem has no way to see files that aren't on a mounted volume.
reverscan works differently. It builds and maintains its own index — a local database on your Mac that stores file metadata, extracted text content, and image thumbnails. When you search, it queries that database, not the live filesystem. The drive doesn't need to be mounted.
How reverscan Keeps Drives Searchable When Unplugged
When reverscan indexes an external drive, everything it discovers gets written to a local SQLite database at ~/.reverscan/index.db. This database lives on your Mac's internal storage — not on the external drive itself.
The database stores:
The full path of every indexed file
The filename and folder structure
Extracted text content (from PDFs, AI files, Sketch files, and other supported formats)
OCR'd text from Deep Scan (for PSDs, design files, and images)
Visual embeddings for image similarity search (JPG and PNG files)
A stored base64 thumbnail preview for each indexed image
When you unplug the drive, the database stays. The next time you search, reverscan queries the database as normal. Files from the disconnected drive appear in results — with an "Unplugged" badge showing which drive they're on.
[SCREENSHOT: reverscan search results showing a file with an "Unplugged" badge, indicating the source drive is not connected]
What You Can Do With Results from an Unplugged Drive
Knowing a file exists on a disconnected drive is genuinely useful even before you plug anything in.
You know which drive to grab. The "Unplugged" badge shows the drive name. If you have five external drives, you know exactly which one to dig out.
You see the thumbnail. For image files (JPG, PNG), reverscan stores a thumbnail preview in the database during indexing. When you search and the result is from a disconnected drive, the thumbnail is still shown — you can visually confirm it's the right file before you connect the drive.
You see the full path. The result shows the complete folder path where the file lives on the drive. You know exactly where to look once the drive is mounted.
You can confirm it's what you need. The content that was indexed — text extracted from the file — remains searchable. A search for specific copy from a document surfaces the match even if the drive isn't connected.
[SCREENSHOT: image search result from an unplugged drive, showing the stored thumbnail preview alongside the filename and "Unplugged" badge]
Try it free → Download reverscan and make every drive you own permanently searchable.
Setting It Up
This works automatically as part of normal indexing. There's no separate "offline mode" to enable. Here's the complete workflow:
Step 1 — Connect the drive and add it to reverscan
Plug in your external drive. Open reverscan and go to the Drives tab. Click + Index Drive / Folder and select the drive. The initial index scan runs automatically.
Step 2 — Run Deep Scan (recommended)
Deep Scan extracts content from design files via OCR and generates visual embeddings for images. This is the step that makes your image thumbnails available for offline preview. Run it from the drive card before you unplug.
Step 3 — Unplug the drive
That's it. The drive is now searchable without being connected. Unplug it, put it in a drawer, ship it to a client — the index remains on your Mac.
Step 4 — Search as normal
Open reverscan, type a query, or drop a file for reverse search. Results from the disconnected drive appear alongside results from connected drives. The "Unplugged" badge identifies which results come from the offline location.
Practical Use Cases
Archive drives in storage
Design work from three years ago lives on a drive you rarely connect. Index it once, put it back in storage. Any time a client comes back for old files or you need a reference from a past project, the drive's contents are searchable from your Mac.
Client asset drives
A client sends their brand assets on a hard drive at the start of a project. You index it, do the project, return or store the drive. Six months later when they come back for revisions, you can search for everything that was on that drive without asking for it again.
Travel and field drives
You have a drive you bring on shoots or to client offices. Back at the studio, it's back in the bag. Everything on it is still searchable from your main machine.
Old backup drives
Backup drives contain years of historical files that are too time-consuming to audit manually. Index them once and treat the reverscan search bar as the interface to that historical library.
Multiple project drives
Running several large projects, each with its own dedicated drive, all kept indexed. Switch between projects without hunting for which drive has which files.
When You Do Need to Plug the Drive Back In
The index tells you a file exists and where it lives. To actually open, copy, or use the file, the drive needs to be connected. reverscan shows the path — plug the drive in, navigate to that path, and you're done.
For image files, if the stored thumbnail is enough to confirm it's the right file, you don't need to connect the drive until you're ready to actually work with it. For other file types, the path and extracted content are your confirmation.
Frequently Asked Questions
How long does the index persist after a drive is unplugged?
Indefinitely. The index doesn't expire or auto-delete. Files from a drive you indexed three years ago and have never reconnected are still in the database and still searchable.
What if files on the drive change after I've indexed it?
The index reflects the drive's state at the last sync. If files were added, modified, or deleted after the last sync, the index won't reflect those changes until you reconnect and sync again. reverscan shows the "Unplugged" badge as a visual reminder that the index may be out of date for that drive.
What if I have many drives with similar content?
Results from multiple drives appear together in the same list. Each result shows its drive name and full path, so you can distinguish between results from different sources.
Does the thumbnail work for all file types?
Currently, stored thumbnails are generated for JPG and PNG image files during indexing. Other file types don't have stored thumbnails — you see the filename, path, and extracted content, but no visual preview.
Can I remove a drive from the index?
Yes. Go to the Drives tab in reverscan, find the drive card, and click Remove. This deletes all indexed data for that drive. The original files on the drive are untouched.
Does this work for network drives or NAS?
reverscan is designed for locally mounted drives (USB, Thunderbolt, SD card). Network-attached storage accessed via SMB/AFP may work if the volume appears as a mounted drive, but it's not a primary use case and offline behaviour for network locations isn't guaranteed.
Every drive you've ever connected to this Mac can be permanently searchable — even from a drawer. Download reverscan free and index your drives today.