How to Back Up and Protect Your Reference Library (2026)

By refern | Last updated: June 2026

Backing up a reference library means protecting two things: the image files themselves, and the index that holds your tags, ratings, descriptions, and folder structure. Miss either one and you either lose images or lose months of curation work. This guide walks through a practical, tool-agnostic backup strategy for artists and designers, then covers the specific considerations for the four most common reference tools: refern, Eagle, PureRef, and BeeRef.

The two things you can lose

Before getting into steps, it helps to understand exactly what is at risk.

Your image files. These are the actual JPGs, PNGs, and other files you have collected. A hardware failure, accidental deletion, or ransomware attack can wipe them permanently if no copy exists elsewhere.

Your index. This is the metadata your tool builds around those files: folder organization, tags, ratings, descriptions, source URLs, color labels, and smart folders. Even if you recover your image files, a lost index means rebuilding months or years of curation from scratch. For a library of thousands of images, that curation effort can be more valuable than the images themselves.

Different tools store these two things very differently, and that difference determines how hard or easy your backup situation is.

How different tools store your library

Understanding what is on disk tells you what you need to back up.

Files-on-disk model (refern)

refern is a local-first desktop reference manager that never copies or moves your original files. Your images stay exactly where you put them, in a normal folder you already own. refern writes two sidecar items into that folder: a SQLite database (refern-db.sqlite) that holds all your metadata, tags, ratings, and search index, and a refern-thumbnails/ folder for fast grid previews.

This model has a significant backup advantage. To back up everything, you back up the folder. One operation covers your images and your entire index together. There is no proprietary container to worry about, no special export step, and no second location that can get out of sync.

Proprietary library folder (Eagle)

Eagle ($34.95 one-time as of 2026) copies every file you import into its own .library folder. This folder is Eagle's proprietary format and contains all your images as copies, plus the metadata database. The upside is that everything is in one place. The downside is that the library folder can be very large (it effectively doubles your disk usage since your originals still exist wherever they were), and you must back up this entire folder to protect yourself. Eagle itself has no built-in cloud backup or sync, so backing up requires a third-party tool such as Dropbox, Google Drive, or an external drive.

Proprietary file format (PureRef)

PureRef (pay-what-you-want for personal use; $49 one-time for commercial use as of 2026) stores your references inside a .pur binary file with images embedded directly. This means your backup situation is board-by-board: you need to back up every .pur file that contains images you want to keep.

The risk here is real. If a .pur file becomes corrupted during a save (for example, during a power outage or when your disk runs out of space), you can lose the images embedded inside it. PureRef forum users have reported losing "months worth of references" to exactly this failure mode. PureRef maintains a .pur.old file as a one-generation backup, but this is not prominently documented and does not cover every scenario.

PureRef also has no tags, no search, and no persistent library across boards, so there is no "index" in the same sense as the other tools. Your backup only needs to cover the .pur files themselves.

Proprietary file format (BeeRef)

BeeRef (free, open source) works similarly to PureRef: it saves each board as a .bee file with images embedded as PNG or JPG data inside a SQLite container. Larger boards with high-resolution references can result in very large files. Back up your .bee files as you would any important document. BeeRef has no library, no tags, and no search, so there is no separate index to protect.

Before you start: audit what you have

Before setting up a backup strategy, spend five minutes understanding what you actually need to protect.

1. Find where your reference files live. In refern, this is the workspace folder you pointed at on setup. In Eagle, look in Preferences for your library location. For PureRef and BeeRef, this is wherever you save your .pur and .bee files.
2. Estimate the total size. A folder with 10,000 images at typical web resolution is roughly 20 to 40 GB. High-resolution photography or RAW files push this higher. Your backup destination needs to hold at least this much space.
3. Identify the index file, if any. For refern, this is refern-db.sqlite inside your workspace folder. For Eagle, the entire .library folder is the index plus images combined. For PureRef and BeeRef, there is no separate index.
4. Check how long since your last backup. If the answer is "never" or "I don't remember," start now.

Step 1: Choose your backup destinations

A reliable backup strategy uses at least two destinations: one local and one offsite.

Local backup (external drive). An external USB or NAS drive gives you fast recovery after a hardware failure and works without internet access. Use a dedicated drive for backups, not the same drive you work from.

Offsite backup (cloud storage). Cloud backup services such as Backblaze Personal Backup ($99/year, unlimited storage), Google Drive, iCloud, or Dropbox give you protection against fire, theft, or physical damage to your home or studio. For large reference libraries (50 GB or more), Backblaze is significantly cheaper per gigabyte than Dropbox or Google Drive.

The rule of thumb for important data is the 3-2-1 rule: three copies total, on two different media types, with one copy offsite. For a reference library, "three copies" might be: the original on your working drive, a copy on an external drive, and a copy in the cloud.

Step 2: Set up automated backup

Manual backups fail because they rely on remembering. Automate as much as possible.

On Windows, use File History (built into Windows 10 and 11) to continuously back up a folder to an external drive. Set it to run hourly or daily. Alternatively, a dedicated tool like FreeFileSync can schedule folder-to-folder copies.

On macOS, Time Machine backs up your entire drive (or selected folders) to an external drive automatically. For cloud backup, Time Machine can back up to a NAS or server; many macOS users add Backblaze as a second cloud layer.

On Linux, rsync with a cron job is the standard approach. A simple rsync -av --delete /path/to/references /path/to/backup scheduled daily covers most cases.

For the cloud layer on any platform, a service like Backblaze Personal Backup runs continuously in the background and backs up everything below your size/type filters automatically, with no manual action needed after setup.

Step 3: Back up the index alongside the images

This step is where most artists make a mistake. They back up the image files but forget the metadata.

refern: Your workspace folder contains both. Back up the entire workspace folder and you automatically protect refern-db.sqlite (all your tags, ratings, descriptions, smart folders, and search index) along with your images. Nothing special to do beyond backing up the folder.

Eagle: Back up the entire .library folder. The metadata database is stored inside the library alongside the image copies. Because Eagle duplicates your files on import, your .library folder is the only place that contains both the images and the organizational metadata in sync.

PureRef: Each .pur file is self-contained. Back up the folder where you store your .pur files. There is no separate database.

BeeRef: Same as PureRef. Back up the folder where your .bee files live.

Step 4: Test a restore

A backup you have never tested is not a backup you can rely on.

Once you have set up your backup, simulate a restore with a small set of files:

1. Copy a folder of 10 to 20 reference images and the associated index file (or board file) to a temporary location.
2. Delete the originals from their normal location.
3. Restore from your backup copy.
4. Open your reference tool and verify the images and metadata appear correctly.

For refern, this means pointing a workspace at the restored folder and confirming that your tags, ratings, and folder structure come back intact. For Eagle, it means opening the restored .library folder and verifying that your library appears as expected. For PureRef and BeeRef, it means opening a restored .pur or .bee file and confirming the images are present.

If the restore works, you have confidence. If it fails, you catch the problem before a real data loss event forces you to find it.

Step 5: Build a routine

Backups degrade over time if you stop running them. Build a simple maintenance habit.

• Weekly: Check that your automated backup ran successfully. Most backup tools send a status notification; look for it.
• Monthly: Verify the backup destination has enough space. A full backup drive stops making new copies silently in some tools.
• Before a major reorganization: Run a manual backup before doing a large tag cleanup, folder restructure, or library migration. If something goes wrong mid-operation, you have a clean snapshot to restore from.
• After importing a large batch: If you import 500 new images and spend an hour tagging them, trigger an immediate backup before closing the session.

Comparison: backup difficulty by tool

How refern handles backup differently

Because refern never copies or moves your original files, your workspace folder is a normal folder you fully own. Every standard backup tool (Time Machine, File History, Backblaze, rsync, Dropbox) works with it without special configuration.

refern also includes periodic automatic backups with one-click restore built into the app. If something goes wrong with the SQLite index (such as a crash during a write), refern can restore from a recent backup in one click from the Settings panel. This is separate from your personal backup strategy but adds a layer of protection for the metadata even if you have not configured an external backup yet.

When you point refern at an existing folder, it indexes the files in place without touching them. If you later decide to use a different tool or stop using refern entirely, your original files are exactly where they were, completely unchanged, and your folder organization is preserved on disk. There is no export step and no lock-in.

For artists currently using Eagle, refern includes an Eagle importer that reads folders, tags, ratings, source URLs, and notes from an Eagle library and brings them into refern. Your curation history transfers. For more on what the canvas and graph features add on top of the library, see the refern vs Eagle comparison and the best Eagle alternatives guide.

Common problems and fixes

"My backup drive ran out of space and stopped backing up months ago." Check your backup tool's status screen. Prune old backup snapshots, archive completed project folders to cold storage (like Backblaze Vault or Amazon Glacier), or add a larger drive. Set a calendar reminder to check backup storage quarterly.

"I lost a PureRef board and the .pur.old file is from three weeks ago." If you do not have a more recent copy from an external backup, the board content from the last three weeks is likely unrecoverable. Going forward, save PureRef boards to a folder that Dropbox or another sync service watches, so each save produces a versioned copy in the cloud.

"My Eagle library folder is 200 GB because Eagle copied everything." Eagle's disk-doubling behavior is by design. Your options are to use a backup service with enough storage for the full library size, to move your .library folder to a drive with more space, or to migrate to a tool that does not duplicate files. refern's Eagle importer can bring your tags and folder structure over without creating a second copy of your images.

"I reorganized my refern workspace folder externally and now some paths look wrong." Run the reconcile function (Dashboard, "Sync with disk") to let refern diff its index against your current folder state and update paths for moved files. Back up before running a large reconcile to have a clean fallback.

Next steps

A backup strategy is the foundation, but organization makes a library useful even after you have protected it. Once your backup is running:

• Learn how refern's tags and smart folders can surface the right image at the right moment without manual browsing.
• If you are migrating from PureRef and want to understand the organizational differences, the refern vs PureRef comparison covers them in detail.
• If you are coming from Eagle, the best Eagle alternatives guide explains what to look for in a replacement.