Documentation

Everything you need to pack, send, and restore DAW sessions with Crate.

Getting Started

Installing Crate

Download the installer for your platform from the download page:

• macOS — Open the .dmg and drag Crate into Applications. Works on Apple Silicon and Intel.
• Windows — Run the .exe installer. Windows 10/11 64-bit. You may see a SmartScreen warning on first run — click "More info" then "Run anyway."
• Linux — Make the .AppImage executable (chmod +x) and run it. Ubuntu 22.04+ recommended.

System Requirements

No GPU required. Encoding speed scales with CPU cores — you can configure the number of parallel workers in Settings. Disk space: Crate needs roughly 1× the session size as temporary scratch space during packing. Memory: packing is the memory-intensive step, because Crate holds audio in RAM while it compresses and verifies it — peak use grows with the size of the session, and above all with the size of the largest single file in it, so RAM headroom is what lets very large sessions pack comfortably. Restoring is much lighter.

First Launch

On first launch, Crate shows a welcome screen. Crate works immediately for unpacking — no purchase required. To pack sessions, you'll need a license key.

The Interface

Crate has a single-screen interface built around drag-and-drop:

• Drop zone — Drag a folder to pack it, or drag a .crate file to unpack it
• Topbar — Shows the Crate logo, a size summary during operations, a ? (docs) button, and a gear (settings) button
• Pack options drawer — Appears after dropping a folder. Configure codec, splitting, recovery, and encryption before packing
• Progress — Real-time progress with stage indicators (analyzing, compressing, verifying, writing)

Packing a Session

1. Drag a session folder onto the Crate window (or click the drop zone to browse)
2. Configure pack options — Choose your codec, split size, recovery, and encryption settings in the drawer that appears
3. Click "Pack" — Crate analyzes your files, compresses audio losslessly, and creates a .crate archive
4. Send the file — Upload the .crate file to Google Drive, Dropbox, WeTransfer, or any method you prefer

What Gets Packed

• Audio files (WAV, AIFF, AIFF-C, CAF, Wave64) — Losslessly compressed using FLAC or WavPack. Every sample is preserved identically.
• Non-audio files (session files, plugin settings, notes, images, MP3, etc.) — Stored as-is, byte-for-byte identical.
• Folder structure — Fully preserved. Your session opens exactly as you left it.
• Metadata — File timestamps (to the nanosecond), permissions, Finder tags, comments, labels and resource forks are preserved and verified. Folder timestamps are set to the restore date so your file browser re-tallies folder sizes correctly. Transient system attributes — download flags and Spotlight's last-opened dates — are deliberately left behind.

Pack from Finder (right-click)

Crate adds Pack with Crate and Unpack with Crate to the Finder right-click menu — installed automatically the first time the app runs. Right-click a session folder and choose Pack with Crate and it packs immediately with your current default settings; no need to open the app first. Right-click a .crate file and choose Unpack with Crate to restore it. Select several items and Crate processes the whole selection, sorting folders to pack from .crate files to unpack.

The menu-bar Quick Bay

Crate lives in your menu bar so a drop target is always one click away. Click the Crate icon to open the Quick Bay, drop folders onto it, and they pack on the spot. The running job shows live progress; anything else you add lines up in a reorderable queue that runs one at a time so your machine stays responsive. Drag queued jobs to reprioritize, or cancel the entire run with one click. Right-click the menu-bar icon for Settings, Check for Updates, and Quit.

Packing many folders at once

Select multiple folders (or a whole album) and pack them in a single gesture from the app, the Quick Bay, or the Finder menu. Crate asks how you'd like them handled:

• One bundle — everything combined into a single .crate, named from the folders you chose.
• Separate crates — a distinct .crate for each folder.

Either way the jobs queue and run one at a time. Drop a mix of folders and .crate files together and Crate routes each correctly — folders are packed, archives are unpacked, nothing is skipped. Packing the same source again writes a new numbered .crate rather than overwriting the previous one.

Unpacking & Restoring

1. Drag a .crate file onto the Crate window
2. Choose a destination — Crate asks where to restore the session
3. Wait for verification — Crate decompresses, restores every file, and verifies SHA-256 checksums
4. Open your DAW — The session is byte-for-byte identical to the original

Encrypted Archives

If the archive was encrypted, Crate will prompt for the passphrase before unpacking. You must use the exact passphrase that was set during packing.

Split Archives

If the archive was split into volumes, drag any volume onto Crate — it will automatically find and reassemble all volumes from the same directory.

Pack Options

Codec

Choose the lossless audio codec used for compression:

• FLAC (default) — The industry-standard lossless codec. Excellent compression, fastest decompression. Best for most sessions.
• WavPack — Slightly better compression on some material, handles AIFF-C and Wave64 natively. Good alternative for edge cases.

Both codecs are completely lossless — your audio is mathematically identical after decompression.

Advanced Options

Click "Advanced" in the pack drawer to reveal splitting, recovery, and encryption settings. These are optional and off by default.

Encode Workers

Found in Settings → Encode workers. This controls how many files Crate compresses or decompresses in parallel — one worker per file, each running on its own CPU core.

• Default (blank/auto) — uses the lesser of your CPU core count or 8. A good balance for most machines.
• Custom value — set between 1 and 64. Higher values use more CPU cores and finish faster, especially on sessions with many files.

Parallelism applies to every CPU-bound phase: SHA-256 hashing, lossless encoding/decoding, and verification. For best results, set this to your total CPU cores minus 1 — this keeps one core free for the UI and system so your machine stays responsive during packing.

Encryption

Crate encrypts archives in-process with the modern age format — ChaCha20-Poly1305 authenticated encryption with a scrypt-derived key. The passphrase is handled entirely in memory; it never touches the command line or disk, so it can't leak through process listings or shell history.

1. Toggle Encrypt on in pack options (under Advanced)
2. Enter a passphrase — make it strong and memorable
3. The recipient will need this exact passphrase to unpack

Splitting into Volumes

Split large archives into smaller volumes for easier uploading:

• Pick a target service (WeTransfer, iCloud, email…) or a custom size — Crate sizes the volumes to land safely under that limit
• Crate creates numbered parts that each carry the Crate icon: session.part001of003.crate, session.part002of003.crate, etc.
• Upload the parts individually — if a transfer fails, only re-upload that part
• The recipient drags the first part onto Crate and all parts in the same folder are reassembled automatically — and Crate tells them if one is missing

Recovery Records (PAR2)

Recovery records add error-correction data so a partially corrupted or incomplete transfer can self-repair without re-downloading.

• Toggle Recovery (PAR2) on in Advanced options
• Set the recovery percentage (default 5%) — higher percentages tolerate more corruption at the cost of larger archives
• On unpack, if Crate detects corruption, it automatically attempts repair using the PAR2 data

Recovery adds roughly the chosen percentage to the archive size. For a 1 GB archive with 5% recovery, expect about 1.05 GB total.

Verification & Integrity

Every file packed by Crate gets a SHA-256 checksum. On unpack, every file is verified against its checksum. If even one bit is wrong, Crate reports it immediately.

What This Means

• No silent corruption — You'll never discover a click or glitch in a mix at 2 AM because a file was corrupted during transfer
• Bit-perfect guarantee — Every sample, every byte of metadata, every session file is verified identical to the original
• Automatic repair — If PAR2 recovery records are included, minor corruption is repaired automatically

Can audio shift or go out of phase?

No — it is mathematically impossible. This is a common and valid concern, especially if you've worked with lossy codecs that add encoder delay or padding. Here's why Crate is different:

Crate verifies the decoded output twice — once at pack time (with verification on, the default) and once at restore time, always. The verification is a byte-for-byte SHA-256 comparison against the original file. This means every single byte must match: the audio samples, the header, the metadata chunks, everything. If even one sample shifted position, the hash would not match.

When a hash mismatch is detected at pack time, Crate automatically falls back to passthrough — storing the file verbatim instead of compressed. The file still arrives byte-perfect; it just doesn't benefit from compression. This "correctness over size" policy means Crate will never ship a file that doesn't match the original.

• No encoder delay — FLAC and WavPack are true lossless codecs, not lossy codecs with a lossless mode. They add zero latency, zero padding, and zero block-alignment samples.
• No metadata alteration — The --keep-foreign-metadata flag (FLAC) and WavPack's wrapper preservation store every chunk (BWF timecode, iXML, cue markers, loop points) byte-for-byte.
• No sample count changes — Crate never parses or modifies sample counts. The codec handles framing internally, and the round-trip hash proves the output is identical.
• Transients, phase, timing — all preserved — Since every byte is identical, there is nothing that could shift. What you packed is exactly what gets restored.

Verify it yourself — with your own tools, not ours

You never have to trust Crate's internal check. Pack a session, restore it to a new folder, then hash both folders with your operating system's own tooling and compare. An empty diff means every byte is identical — proven independently of Crate.

# Pack (verification is "full" by default), then restore to a fresh folder.
# Then compare the two trees with the OS's own SHA-256 — never Crate's:

# macOS / Linux
( cd "My Session" && find . -type f ! -name .DS_Store -exec shasum -a 256 {} \; ) | sort > original.txt
( cd "Restored"   && find . -type f ! -name .DS_Store ! -name 'CRATE-*' -exec shasum -a 256 {} \; ) | sort > restored.txt
diff original.txt restored.txt && echo "byte-identical ✓"

# Windows (PowerShell)
Get-ChildItem -Recurse -File "My Session" | Get-FileHash -Algorithm SHA256 | Sort-Object Hash

We ran exactly this on a real 1.2 GB Pro Tools mix session (600+ files): every file confirmed identical by the OS itself, while the session shrank ~60%. The point isn't that we say it's bit-perfect — it's that your computer agrees, using tools we have no hand in.

Never locked in

The same open-tools spirit applies to the format itself: a .crate is a standard 7-Zip container of standard FLAC/WavPack audio plus a readable JSON manifest, and a Standard-preset pack opens today with free 7-Zip and the free codec tools — no Crate software required. Read the full no-lock-in story, including the release gate and sunset pledge that cover every compression tier.

Licensing

How Licensing Works

• Unpacking is always free — No license needed to open and restore .crate files
• Packing requires a license — A one-time purchase unlocks packing forever
• No account needed — Your license is a key you paste into the app. No login, no cloud, works fully offline
• All updates included — Paid upgrades are rare, if ever

Activating Your License

1. Open Crate and click the gear icon (Settings)
2. Go to the License section
3. Paste your license key (starts with CRATE1.)
4. Click Activate — packing is now unlocked

Lost Your License Key?

Your license key was emailed to you after purchase. If you can't find it:

1. Check your spam/junk folder for an email from Crate
2. Use the license recovery tool — enter your purchase email and we'll re-send your key
3. In the app, click "Lost your key?" in Settings → License to email support directly

Buying a License

Purchase at crate.fluxcode.studio. We use Purchasing Power Parity pricing — the price adjusts based on your country so Crate is accessible everywhere.

Supported Formats

Losslessly Compressed (audio)

Stored As-Is (already compressed or non-audio)

• MP3, AAC, FLAC, OGG, OPUS — already compressed, stored byte-for-byte
• Session files — Pro Tools (.ptx), Logic (.logicx), Ableton (.als), Cubase (.cpr), Studio One (.song), Reaper (.rpp), FL Studio (.flp), Bitwig (.bwproject), and any other format
• Plugin presets, images, notes, text files, videos — everything in the folder is preserved
• RF64, BW64 — preserved byte-for-byte as passthrough

Compatible DAWs

Crate is DAW-agnostic — it works at the file level. Any DAW that saves files to disk works with Crate:

Pro Tools · Logic Pro · Ableton Live · Cubase · Nuendo · Studio One · Reaper · FL Studio · Bitwig · Pyramix · SADiE · and more

Troubleshooting

"Pack" button is disabled

You need an active license to pack. Go to Settings → License and paste your key. If you don't have one, purchase a license.

macOS: "Crate can't be opened because it is from an unidentified developer"

Crate is signed and notarized by Apple. If you still see this message, right-click the app and choose Open, then click Open in the dialog. This only needs to be done once.

Windows: SmartScreen warning

Windows may show a SmartScreen warning for new software. Click "More info" then "Run anyway". This is normal for new applications and will resolve as Crate gains reputation with Microsoft.

Archive won't unpack — "checksum mismatch"

The file was corrupted during transfer. Options:

• If the archive has PAR2 recovery records, Crate will attempt automatic repair
• Re-download the file and try again
• If the archive was split, check that all volumes are in the same folder and none are truncated

Archive won't unpack — "wrong passphrase"

The archive was encrypted and you're entering the wrong passphrase. Passphrases are case-sensitive. Contact the sender for the correct passphrase.

Missing volumes

If a split archive is missing volumes, Crate will tell you which ones are missing. Download the missing volumes and place them in the same folder as the others.

Session won't relink in my DAW

Crate restores files to the exact same relative paths. If your DAW can't find files:

• Make sure you unpacked to the correct location
• Use your DAW's "Relink" or "Find Missing Files" feature and point it to the unpacked folder
• Check that the folder structure wasn't modified after unpacking

Packing is slow

Compression speed depends on your CPU and disk speed. Tips:

• Pack from an SSD for faster reads
• Close other CPU-intensive applications
• FLAC is generally faster than WavPack for both packing and unpacking

Keyboard Shortcuts

• Esc — Cancel current operation / close dialogs
• Cmd/Ctrl + , — Open Settings