The macOS story starts with good news: Gerbv 2.13.0 is the first release to ship an official macOS build, distributed as a ZIP — there is no .dmg, so do not go hunting for one or download a supposed .dmg from anywhere else. The friction arrives after the download. You extract the ZIP, try to open the app, and macOS declines: Gatekeeper, the system’s check on software from outside the App Store, is treating an app it does not recognise as a risk. For unsigned applications — apps distributed without an Apple developer signature — that caution is routine, and macOS provides a deliberate, per-app way through it. This guide gives that way, in the safe order: verify the download’s hash first, then use the right-click Open method for this one app, and never weaken Gatekeeper for the whole system. The complete installation flow is in install Gerbv on macOS; get the ZIP itself from the download page.
Step 1: Extract the ZIP and see what you actually have
Download gerbv_v2.13.0_.macOS.zip (6,795,082 bytes) and extract it in your Downloads folder or wherever you keep applications-in-progress. Extraction itself can be the first small stumbling block: if a double-click on the ZIP appears to do nothing, look for the extracted folder beside the archive before downloading again, because macOS extracts quietly. Inside, you should find the Gerbv application bundle. Do not move it into Applications yet — keep this first launch controlled and local, confirm the app runs, and only then file it away properly. If what extracted is not an application bundle, or the archive name differs from the one above, stop and re-download through the download page rather than improvising with an unexpected file.
Step 2: Verify the SHA-256 before the first open
The published SHA-256 for the Gerbv 2.13.0 macOS ZIP is:
7d79adf7556508baa6c9d080949866371cbb49809f2082e0e6639cb62c4dba0f
macOS can check this with a built-in command. Open Terminal, change to the folder holding the ZIP, and run:
shasum -a 256 gerbv_v2.13.0_.macOS.zip
Compare the printed value with the one above. An exact match means the archive on your disk is the published release archive, and proceeding past Gatekeeper is a decision you are making about verified software. A mismatch means the opposite: delete the file, re-download through the download page, and check again — no right-click technique legitimises a file whose bytes are not the release. Verify the ZIP, not just the extracted app, because the ZIP is the artefact the project published and hashed.
Step 3: Open the unsigned app the per-app way
With a verified download, handle Gatekeeper as general macOS guidance describes for unsigned apps you have chosen to trust on evidence. Do not double-click for this first launch — a plain double-click is what Gatekeeper blocks. Instead, right-click (or Control-click) the app and choose Open from the context menu. macOS then shows a dialog naming the app and asking whether you are sure you want to open it; confirm Open. That single confirmed open records your decision for that app, and subsequent launches work normally by double-click. If you instead find a note in your security settings saying the app was blocked, with an option to open it anyway there, that is the same per-app decision reached by another door — use whichever macOS presents, provided the app named is the Gerbv you just verified, and provided you reach it immediately after your own blocked launch rather than finding a stale entry from some earlier, forgotten attempt.
What not to do
Do not disable Gatekeeper globally. As general macOS guidance, the system-wide off switch exists for managed environments, not as a consumer fix: it removes the check for every future download, including the malicious one that will eventually arrive dressed as something you wanted. The right-click method exists precisely so that one verified app can be excepted while the protection stands for everything else. Likewise, do not strip security attributes from the app with terminal commands copied from a forum, and do not re-download from a site promising a pre-unblocked or installer-wrapped copy — the ZIP on the download page, hash-verified, is the entire supply chain you need. Finally, if a first launch still fails after a verified hash and a confirmed Open, read any message macOS shows word for word before acting; platform issues beyond Gatekeeper are handled in the macOS install guide, and guessing at system settings helps none of them.
After the first open
Once Gerbv runs, move the app to Applications if you have not already, and open a first board set following how to open Gerber files so the session ends with the viewer doing its actual job. An alternative installation route also exists — Homebrew lists Gerbv 2.13.0 — and the install guide discusses when that route suits better than the ZIP. Either way, the Gatekeeper lesson transfers to other small open-source Mac software: verify first, except per-app, and leave the system protection switched on.
Prevention
For future releases, repeat the same two-minute shape: download the new ZIP from the download page, check its published hash for that version (hashes are per-file and per-release — never reuse this version’s value for the next), and right-click Open on first launch. The habit costs almost nothing and converts Gatekeeper from an annoyance into what it is designed to be — the moment you pause and prove what you are about to run.
Frequently asked questions
Why does Gatekeeper block Gerbv on macOS?
The 2.13.0 macOS build is distributed as an unsigned application outside the App Store, and Gatekeeper treats unrecognised, unsigned apps cautiously by default. Verify the ZIP’s SHA-256 first, then use the per-app Open method rather than changing system settings.
Is there a .dmg installer for Gerbv on macOS?
No. The official macOS artefact for 2.13.0 is a ZIP — the first official macOS build shipped in that release. A supposed Gerbv .dmg from another site is not the project’s release and should not be used.
Should I disable Gatekeeper to install Gerbv?
No. Disabling Gatekeeper removes the check for all future downloads. Right-click the verified app, choose Open, and confirm once — that excepts this one app while system protection stays on for everything else.