How large is your Aperture library? And what do you mean by
with 5gb maximum transfer please
? Please explain.
If you connect your external hdd directly to your Mac (USB, FireWire, Thunderbolt), you can simply drag your library to the external drive using drag and drop in the Finder.
Make sure, the external hdd is formatted Mac OS X Extended (Journaled), before you transfer the library. Aperture will not work with a disk in a different format.
After transferring the library double click it to open it in Aperture. if you have referenced originals, use the command "File > relocate originals" to move the original image files to your external drive.
This suggestion may not work: I see from the answer of Leonie that Aperture does not work with FAT.
This means you can follow my suggestion to split the library on your local drive and then move them to the FAT drive but this could be only a sort of backup.
Do you have your stuff arranged into Projects I believe.
Check the total size of your library and extimate how many new library you have to create to split it and get less than 5GB.
Lets imagine you need 3.
Open Aperture and select 1/3 of Projects (decide from the number of picture each contains).
Right click on them and select Export.... Export Project as new library....
Repeat for the other.
Check if the new library works and are complete. You may not delete the original library.
Message was edited by: WALTER-MILANO-ITALY
the limit is because my hard drive is formated for "fat" giving it a maximum transfer of 5gb at a time for a single file. The split sounds interesting how is this done please
Aperture will refuse to work with a volume formatted MS-DOS (FAT), at least the the most recent Aperture versions, Aperture 3.x.x..And even with earlier version you will be in for much trouble and can expect plenty of broken references to original image files, lost original files, etc.
I strongly recommend to reformat the drive, or at least put the library on a partion formatted correctly, or a disk image formatted correctly.
This support article explains, how to put the library onto a disk image, if you need it on a drive with a different filesystem. Never mind, that this is written for iPhoto - both application share the same library format: http://support.apple.com/kb/HT1198