If you received message with the following content, it means that your Mac already has a potentially conflicting driver installed.
If you want to use one of these applications correctly you should disable the unnecessary one in Preferences menu.
You can disable SyncMate driver in Preferences menu, if you don’t want to use it as default synchronizer. In this case click "Disable USB module" button.
Perhaps, some synchronization software (Missing Sync, PocketMac, etc.) wasn’t properly uninstalled so an invisible usb driver is still present in the system. It doesn’t allow to connect when you install SyncMate. In that case it’s recommended to completely uninstall the software.
To uninstall Missing Sync please use its uninstaller and make sure that the following files are not present in your system:
1. \library\Application support\Missing Sync for Windows Mobile
2. \system\library\extensions\MissingSyncWM.kext
After that please install the latest version of SyncMate (http://www.sync-mac.com/download/syncmate.dmg).