Help

Before you download

The Mac package will not open: “the application cannot be opened”.

Almost always an Intel Mac. MyDiveLog is built for Apple Silicon only: the package installs anyway, and then the app will not start. You need an Apple-silicon Mac and macOS 12 or later. There is no Intel build, and none is planned.

Windows says it doesn’t know us.

“More info” → “Run anyway”. The file is signed, just not for long enough for Windows to have formed an opinion about us — it happens to anyone who does not pay for EV certification. The SHA-256 fingerprint published next to the package tells you whether the file you have is ours.

Android asks permission to install from this source.

It happens with the APK, and it is the same question Android asks for any app from outside the Play Store; from Google Play it does not ask. The APK cannot vouch for its own origin: the SHA-256 fingerprint in the release notes can.

I have the APK from the site: can I move to Google Play?

Yes, but not on top of it: the APK and the Play copy have different signatures, and Android does not let one update the other. First save everything from Settings → Full backup and restore, then uninstall the APK, install from Play and restore the backup. Without a backup, uninstalling deletes your dives from the phone.

The Linux package will not install: libwebkit2gtk-4.1-0 is missing.

The .deb needs WebKitGTK 4.1, available from Ubuntu 24.04 and Debian 13 onwards. Older distributions only have 4.0 and this package will not go in — that is not a fault of the package, that library simply is not there. On Ubuntu 22.04 there is no route for now.

I am on Arch or Manjaro: the .deb will not install.

There is no dpkg, but the package can be repackaged for pacman with four commands — nothing to compile, the binary is the same:
sudo pacman -S --needed base-devel
mkdir mydivelog && cd mydivelog
curl -LO https://raw.githubusercontent.com/matteoferrando/MyDiveLog/main/linux/PKGBUILD
makepkg -si
makepkg stops if the file’s checksum is not the declared one. Tested on Manjaro.

Can I install it with Homebrew?

Yes, from our own tap, in one command:
brew install --cask matteoferrando/mydivelog/mydivelog
The full name tells Homebrew to trust this cask, and only this one. If you installed it earlier with brew tap, Homebrew now ignores it until you tell it to, once:
brew trust --cask matteoferrando/mydivelog/mydivelog
The app keeps updating itself in the meantime, as always.

Your dive computer

I press “Find my computer” and nothing shows up.

Nine times out of ten it is the Bluetooth permission. It is the first thing that stopped this application’s first outside user, and the error was not clear: the app now says where to grant it. On macOS: System Settings → Privacy & Security → Bluetooth. On iPhone: Settings → MyDiveLog → Bluetooth. Then check the computer is on and in pairing mode: many only make themselves visible for a few minutes after you ask them to.

The download fails: there is a “Try another way” button.

Use it. Talking to a dive computer over Bluetooth means making five choices — which service to talk to, which channel to write on, which one to listen to, whether to wait for confirmation of every write, and how to reassemble the replies — and the first guess is not always right. The button tries the next combination and tells you how many are left; when one works, the app remembers it for that computer and goes straight there next time. It only changes how the app talks to it, never how the data is read: none of those choices can put wrong numbers in your logbook.

The computer is asking me for a six-digit code.

That is normal, and it happens with the Aqualung i330R, i330R Console and Apeks DSX: when you connect them they show a number on their own screen and want you to type it back. The number appears after the first connection attempt, so do not go looking for it beforehand. You only type it once: the computer hands back a key that the app keeps, and from then on it connects straight away. If it ever asks again — because you reset the computer or paired it with another phone — that key had stopped working, and it was dropped automatically.

My computer is not in the list.

From a phone only Bluetooth LE is reachable: serial ports and USB do not exist there, and classic Bluetooth is reserved for system profiles — and the same holds on the desktop, because we do not open serial ports or USB on any platform. Of the 358 models libdivecomputer describes, 115 are ones we can actually download, and that is the list. If your computer writes a file — UDDF, Shearwater, Subsurface, LogTRAK, Garmin FIT, CSV — you can import it instead, and that road is just as good.

I downloaded twice: will dives be duplicated?

No. From the second connection on it takes only the new dives, and the ones already there are enriched rather than duplicated. The same holds when one dive arrives by two different roads — over Bluetooth and from an exported file.

Two computers show different times. Will dives be split in two?

No: the offset between the two clocks is inferred across your whole logbook, and the match is confirmed on the shape of the profile, not on the timestamp. Every dive lists the sources it was built from, so when a value is missing you know which computer never wrote it.

Your data

Where are my dives?

On your device, in a SQLite file you can open with anything. On a Mac it lives in ~/Library/Application Support/it.ferrando.mydivelog. We keep no copy: if you do not sign in and do not press Sync, nothing leaves the device.

How do I back it up?

Settings → full JSON backup. It is the only one that puts everything back the way it was, gear and certifications included. The UDDF, CSV and KML exports are for taking dives elsewhere, not for rebuilding the archive.

Do I need an account?

No. The logbook opens, imports and analyses without ever seeing an account. Signing in — with Apple or Google — does one thing only: keeps the archive aligned across devices. And even then, syncing starts when you press it.

I want to leave: can I take everything with me?

JSON backup, UDDF, CSV and KML export, logbook PDF. And the archive is a SQLite file: worst case you open it with anything and take the tables by hand.

The numbers

The calculations do not match my dive computer.

That is normal, and it is right to look at them with suspicion. Every dive computer uses its own implementation, and conservatism settings rarely line up. MyDiveLog uses Bühlmann ZH-L16C with gradient factors, and under every number it states how reliable it is and how many dives it rests on.

The VPM-B plan is shorter than V-Planner’s.

Yes, by 5 to 10 per cent, and it is stated inside the application too. This is not a calibration: it is a difference we have not explained yet, and until we do it stays declared rather than hidden.

There’s no consumption figure: the box only says the cylinder data is missing.

That happens with most dive computers, which have no air integration: without cylinder pressures the figure cannot be worked out, and inventing one would be worse than leaving it empty. If you have worked it out yourself from the pressure gauge, you can now type it in: open the dive, Edit, and under the cylinders there is Surface consumption (L/min), if you work it out yourself. It counts for the dive, the statistics and the logbook sheet, and it stays marked as entered by you — on the dive and on the sheet. Where the pressures do exist, the calculation wins: a measured figure is never replaced by a typed one.

I switched gas during the dive: does MyDiveLog see it?

Yes, if the computer recorded it. Tissue loading, CNS, OTU and the check on the depth of the switch all use the gas you were actually breathing at each moment, not the bottom mix for the whole dive. The gas comes from the computer at download time: dives already in your logbook do not have it, and to get it they have to be downloaded again with Download everything from scratch ticked. Downloading again duplicates nothing — the dives you already have are enriched, and notes, site and weights stay where they are.

Can I use it to make decisions in the water?

No. MyDiveLog is not a dive computer. The calculations exist to study the dives you have done and prepare the ones you are going to do: they do not replace your dive computer, your training or your judgement. Scuba diving carries risks, including death.

The logbook and the law

How do I get the PDF logbook page?

Open the dive and press Export PDF: out comes a page with the thirteen entries the law asks for, the profile drawn, and the guide’s signature. It works from the phone too — the phone is where you need it — and you send the file to whoever asks without going home first.

Is the app “legally compliant”?

It holds the fields the rule lists. Compliance, though, belongs to whoever fills the logbook in, not to a program — and the law leaves more than one question open. The page on the logbook law writes them all down, including the ones without an answer.

Updates and reports

How does it update?

Mac and Windows tell you when a new version is out; downloading and installing it is your call, and every update is signed. The Android APK and the Linux package do not: you get the file again from here. If you installed from Google Play, Play delivers it; from the App Store or the Mac App Store, Apple does, like any other app.

I found something wrong.

Tell us here: two lines are enough. This application’s first outside user found a real defect by pressing a button, and that defect was out of reach of every automated test. Reports are how this project gets better.