[Update May 2020] As you would expect, the lack of Rosetta in macOS after 10.7 means these units are finally obsolete on macOS. Not that I can believe anyone is still trying to use one of these, though my Google stats tell me differently - this article still generates traffic so it seems there are a few out there in use still.
If you still have one of the old Emagic USB interfaces, the emi 2|6 & 6|2m or the briefly rebranded A26 & A62m, you may have been annoyed that they no longer appear to function in OSX 10.6 Snow Leopard. However, the fix is relatively simple, you just need to fix the permissions for the firmware loader. Grab the last installer from the Apple ftp and run it (you will need Rosetta installed for this, 10.6 will offer to d/l and install for you if necessary). Open a Terminal and do the following :-
sudo chown -R root:wheel /Library/StartupItems/EmagicA26A62mFirmwareLoader
sudo chmod -R 755 /Library/StartupItems/EmagicA26A62mFirmwareLoader
sudo chmod 644 /Library/StartupItems/EmagicA26A62mFirmwareLoader/StartupParameters.plist
Next, delete the relevant preference pane in /Library/PreferencePanes/ – it’s a PPC pane so there’s no need to keep it hanging around. Finally reboot & watch it spring to life.