Stuffit Expander has been the Mac file compression and decompression tool for decades. These days, its proprietary .SIT format is less popular than the open .ZIP system - which Mac OS X supports natively - but SE is still handy to decode a raft of widely used compression formats: .TAR, .RAR, .CBZ and .CBR, for example. Only an unnecessarily tiresome register-to-download acquisition process stops us rating this handy tool more highly.
Reg Rating 65
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Carbon Copy Cloner
Mac OS X's Time Machine feature is a great automated back-up system that will meet most users' needs. If your Mac's hard drive goes tits up - God forbid - it will restore your data on to a new machine or rebuilt system. But you will have to reinstall all your apps and, if you're rebuilding, the OS too. Mike Bombich's Carbon Copy Cloner allows you to copy everything - the entire HDD bit for bit - making restorations much more straightforward. It has plenty of back-up options too, including back-up to another Mac across a network, all useful if you have very specific back-up needs Time Machine won't meet. Even if TM does, CCC is the best way of migrating from Mac to Mac.
Reg Rating 75
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Ten free apps to install on every new Mac
Free, open-source video transcoder. It just works and has some reasonable default template settings for the non-technically literate (like me).
I haven't had to bother with the Stuffit signup annoyances ever since I discovered "The Unarchiver", which handles at least as many formats (if not more) and is free and open source. The author seems readily available on his site to take bug reports and feature requests too, not that bugs seem too common.
Perian is a free, open source QuickTime component that adds native support for many popular video formats.
This free plug-in gives codec support to QuickTime for all major video formats, including OGG and MKV, as well as subtitle support. While it is a close second to VLC for its formats, the fact that it integrates into QuickTime and therefore exports videos is a huge boon.
Side note: The Squared 5 MPEG Streamclip download link is broken.
i found carbon copy cloner to be a bit annoying. superduper is really easy and the paid version allows you to do stuff i have never needed.