Is LocalSynapse really free?

Yes. Document search is completely free with no limits — no file count caps, no trial period, no feature gates. The only paid feature will be email search integration (coming later as a Pro add-on). Everything else stays free forever.

Does it upload my files to the cloud?

No. LocalSynapse is 100% offline. All indexing, AI processing, and search happen on your PC. No files or data are ever sent to external servers. No internet connection is needed after installation.

What file formats are supported?

LocalSynapse searches inside Word (.docx), Excel (.xlsx), PowerPoint (.pptx), PDF, HWP (Korean word processor), RTF, plain text files (.txt, .csv, .json, .xml, .md), and more — 13+ formats in total. It also searches filenames of all file types.

How is this different from Everything Search?

Everything is excellent for finding files by name — it's the fastest filename search on Windows. LocalSynapse goes further: it searches inside your documents by content, groups related file versions automatically, and uses AI semantic search to find files even when you don't remember the exact words.

What are the system requirements?

Windows 10/11 or macOS 12+, 8GB RAM recommended (4GB minimum), and about 500MB disk space including the AI model. LocalSynapse runs on CPU — no GPU required.

What is the MCP server?

MCP (Model Context Protocol) lets AI agents like Claude and Cursor search your local files. LocalSynapse includes a built-in MCP server — same app, just run it with 'LocalSynapse mcp' to start the server.

Your files never leave your machine. The AI model runs locally via ONNX Runtime. The search index is stored in a local SQLite database. There's no telemetry, no analytics on your file contents, and no network calls during search.

How do I install LocalSynapse on macOS?

Download the .dmg, drag the app to Applications, then open it. Because the app is not signed with an Apple certificate, macOS may show a Gatekeeper warning. Two ways to bypass it: (1) Control+Click the app icon → Open → Open again. (2) Run 'xattr -cr /Applications/LocalSynapse.app' in Terminal. You only need to do this once.

Does it search files in OneDrive, Google Drive, or iCloud?

It searches files that are physically downloaded to your disk. Cloud-only placeholders (OneDrive Files On-Demand, iCloud optimized storage) are skipped — there's nothing to search inside them locally. The Data Setup page shows a count of skipped files with the reason. To index them, mark the files as 'Always keep on this device' in your cloud client.

How to Install LocalSynapse on macOS (Gatekeeper Workaround)

Name: LocalSynapse
Author: LocalSynapse

2026-04-11·3 min read

Quick Answer: Drag LocalSynapse.app to Applications. On first launch, Control+Click the icon → Open → Open again. Or run 'xattr -cr /Applications/LocalSynapse.app' in Terminal. You only need to do this once.

LocalSynapse runs on macOS 12 and later, on both Intel and Apple Silicon Macs. But because the app is not signed with an Apple Developer certificate, macOS Gatekeeper will refuse to open it on first launch with a message like "LocalSynapse is damaged and can't be opened" or "developer cannot be verified". Here's how to install it safely.

Step 1 — Download the right .dmg

Go to localsynapse.com, enter your email, and you'll see two macOS download links:

macOS (Apple Silicon) — for M1, M2, M3, M4 Macs (most Macs sold after late 2020).
macOS (Intel) — for older Intel-based Macs.

Not sure which one you have? Click the Apple menu → About This Mac. If you see "Apple M1/M2/M3/M4" under Chip, get the Apple Silicon build. If you see "Intel Core...", get the Intel build.

Step 2 — Mount the .dmg and drag to Applications

Double-click the downloaded .dmg file. A window will open showing the LocalSynapse app icon and an Applications folder shortcut. Drag the app onto the Applications folder. Eject the .dmg.

Step 3 — First launch: bypass Gatekeeper

This is the part that trips people up. If you double-click LocalSynapse like a normal app, macOS will block it. You have two options:

Option A: Control+Click → Open (the easy way)

Open the Applications folder in Finder.
Control+Click (or right-click) the LocalSynapse icon.
Choose Open from the menu.
A warning dialog appears. Click Open again.

That's it. macOS now trusts the app and you can launch it normally from now on.

Option B: Terminal (one-liner)

If Option A doesn't work, or you prefer the command line, open Terminal and run:

xattr -cr /Applications/LocalSynapse.app

This removes the quarantine attribute that macOS attaches to apps downloaded from the internet. After running this, you can launch LocalSynapse normally with a double-click.

Why is the Gatekeeper warning showing?

macOS Gatekeeper checks every new app for two things: a valid Developer ID signature, and notarization (Apple has scanned the app for malware). LocalSynapse uses ad-hoc code signing for now — it's signed, but not with an Apple Developer ID, so Gatekeeper treats it as untrusted on first launch.

Apple Developer notarization costs $99/year. We're a free, open-source project, and we'd rather put that toward something users actually feel. The workarounds above let you verify and trust the app yourself — which is functionally the same thing Gatekeeper does, just with you in the loop.

Is it safe?

LocalSynapse is open source under Apache 2.0. You can read every line of code at github.com/LocalSynapse/LocalSynapse. The releases on GitHub include SHA-256 checksums (SHA256SUMS-macOS.txt) — you can verify the file you downloaded matches what was built and published. Once installed, the app makes zero outbound network calls during search.

System requirements

macOS 12 (Monterey) or later
Apple Silicon (M1+) or Intel (x64)
8 GB RAM recommended (4 GB minimum)
~500 MB disk including the AI model

Once installed, LocalSynapse scans your home directory and builds the search index in the background. You can start searching filenames immediately; content search becomes available as indexing progresses.

Get LocalSynapse for macOS →