The digital dive log for macOS and iOS


The Basics


Importing and Downloading data


Troubleshooting Downloads

Install the appropriate USB driver

Some devices require a USB driver. Please visit the Devices Page and check whether or not yours does. If it does, install it prior to attempting a download. If you need a hand, then simply drop us an and we'll be happy to help.

Transfer Mode

Some Dive Computers will automatically enter "Data Transfer" or "PC Transfer" mode, and some will not. If yours doesn't appear to do so automatically, it may be worth checking your user manual to find out how to enable download mode.

Choose The Appropriate Device

Make sure you choose the correct model when you download from your device. In some cases there are similar models that will download as expected, but in others the specific model is necessary. If you encounter any issues downloading from your device, please make sure you have the correct model specified.

Error Messages

No devices found

This error indicates that MacDive could not find any devices attached to your computer. Check that your dive computer is plugged in, and that you've chosen the correct model to download.

Could not detect a valid serial port

Some devices need a USB driver in order to download. Please see the Devices Page if you receive this message and confirm whether you need to install a USB driver. If you have installed it and still receive the message, then try rebooting. This can help kickstart things if they didn't "start" properly the first time.

Failed to connect on serial port XXX

This error means that MacDive failed to connect to a serial port that it thinks is worth trying. For devices that do not require a USB driver, this could mean that it couldn't find the device and connect, and then tried to see if there was a serial port (perhaps from an alternate USB driver) that was worth trying. For devices that do require a driver, it is simply a failure to connect on the specified port.

One cause of this error is that the device is not in PC Transfer mode. Another cause is that MacDive has guessed the wrong serial port. You can visit Preferences > Advanced and override the serial port. Check the dropdown box and try alternate options (ones you haven't seen in the error message) if you're having trouble. If you're not sure what to use, and MacDive hasn't guessed correctly, us and we can help you out. Generally this is not required, and if it is, it's usually a one-off step. We're always working to improve the smarts here so if you run in to trouble then please let us know!

Failed to read header information

This error often indicates that the device was plugged in, but not in PC Transfer mode. Check that the device is set to transfer data to your computer.

It can also mean you have a bad connection. Make sure the connection is solid, the contacts are not dirty, the cable is not damaged, etc.

USB Hubs

Using a USB hub can cause issues with some devices. If you're having trouble downloading, try plugging your dive computer directly in to your Mac.


This sounds really silly. But some of the connectors used on dive computers aren't great, and simply jiggling the cable around and making sure it's really on properly can help.

Low Battery

Low battery can cause downloads to fail, either immediately or part-way through. If you have a low battery and you're running in to problems - particularly if you have been downloading without problem before - then change your battery first. You won't lose any dives, but you'll likely find that the download starts working again.

If all else fails..

Then don't hesitate to get in touch with us. Drop us an and let us know what kind of dive computer you have, which USB driver you installed, what kind of cable you are using (eg the official manufacturer cable, a third party one, etc), whether you've downloaded before, whether you have a low battery, etc. We'll be happy to help you get things working.

Device Specific Notes

This section contains information on common issues with various models of dive computer.

Atomic Aquatics Cobalt

When you go to enable USB mode under Settings, ensure you press select a second time and you see the green "CONNECTED!" text. On the Cobalt 2, you may not see this text - but you'll still need to press the select button a second time.


Ensure you are at the main menu when attempting a download.

Oceanic VT4

If you have problems connecting, make sure your cable is plugged in the right way. The connector fits both ways in to the dive computer, but the download will only work if it is plugged in the right way up. If you have problems, try flipping it over.

Oceanic Pro Plus 2.1 / 3.0

The most common problem with these is the same as the VT4 - the cable plugged in upside down! If you have trouble downloading, then try plugging it in the other way around.

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