The current version of Garmin Express for Mac requires OS X 10.7 or higher.
When attempting to install the current version of Garmin Express on a Mac that does not meet the application's minimum system requirements, the message "Garmin Express is not compatible with your operating system" is displayed.
A Mac running OS X 10.6.8 has a few options for updating the maps on a compatible GPS device:
Garmin Express 2.1.11 can only be run on a Mac with a 64-bit processor, whereas the Garmin Map Updater can be run on both 32 and 64-bit Macs.
To determine whether a Mac has a 32-bit or 64-bit processor, refer to the following support page from Apple:
High Speed Cable or DSL Internet access is required. Not for use with Dial-up, Satellite or Mobile Broadband Internet access. Upon completion, the maps will be installed to the device.
1 Garmin Express 2.1.11 System Requirements:
2Garmin Map Updater System Requirements: