what does time machine backup?

TM backs up everything on all internal drives by default, except some cache and log files. It doesn't automatically back up external drives. Restoring from a TM snapshot gets you a complete bootable system with all data, except as noted.

appleiser wrote:

Just wondering what time machine actually backs up?

As Linc says, everything but things like system work files, most logs and caches, and trash.

You might want to review the Time Machine Tutorial, and perhaps browse Time Machine - Frequently Asked Questions.

Also, say if I installed Mountain Lion onto a blank drive, can I restore my files from a Time Machine backup of Lion during the setup process?

Yup. That's even called Setup Assistant. See How do I set up a new Mac from an old one, its backups, or a PC?

appleiser wrote:

So if I want to Install Mountain Lion on a blank drive and start fresh (not install all my old preference files etc), how do you suggest going about it? Should I clone my internal drive to an external, then wipe my internal and install Mountain Lion on there, then drag and drop what I want from the external??

That will work for most things. But "complex" apps won't work right, if at all. See Transferring Applications for an explanation. You'll have to reinstall them from the original discs or re-download them. And re-enter any serial numbers or purchase keys for them (as well as "simple" apps you can just copy).

Or should I just upgrade and then use one of those third party apps that claim to "clean" your computer (I never really knew if they were worth the trouble...)??

Most of them cause far more trouble than they fix.

If there are things you don't want or need, delete them (but be sure they're well backed-up first, just in case).

So here is my issue i am having.. i need to get a new harddrive since mine is full, what is the best way to go about backing my files and mac os up so i can put it on a new hard drive? Hope you can help! thanks!

You can use Time Machine or one of the 3rd-party "cloning" apps.

Either way, if your data is important, you should continue making regular backups. All disk drives fail, sooner or later (a few fail very early); various things can corrupt the data on your system beyond repair; users make mistakes now and then and change or delete the wrong things; if you have a laptop Mac, they sometimes get lost or stolen.

You'll need an external HD to back up to. If you have a laptop, you may want to spend the extra money to get a Time Capsule (combination of wireless router and HD) so you can back up over your network.

Either way, if you use Time Machine, the backup drive should be at least 2-3 times the size of the data it's backing-up, as it keeps copies of things you've changed or deleted, so needs extra space. If you use one of the "cloning" apps, you can use one the size of your internal HD.

For info on Time Machine, you might want to review the Time Machine Tutorial, and perhaps browse Time Machine - Frequently Asked Questions.

See the green box in #27 in the FAQ link for some info on alternatives to Time Machine.

Once the new HD is installed and formatted, restore the backups to it. If you use Time Machine, see #14 in the FAQ. If you use a "cloning" app, re-clone from the external HD to the new HD.

I have a 500 gb my passport with a firewire and thunderbolt connection options. do you think that will do the work if i back up it up with time machine. or can you suggest a good third party cloning app?

fatcubed wrote:

I have a 500 gb my passport with a firewire and thunderbolt connection options.

If you use Time Machine, the backup drive should be at least 2-3 times the size of the data it's backing-up, as it keeps copies of things you've changed or deleted, so needs extra space. If you use one of the "cloning" apps, you can use one the size of your internal HD.

do you think that will do the work if i back up it up with time machine. or can you suggest a good third party cloning app?

See the green box inTime Machine - Frequently Asked Question #27.

sorry i missed that last part! thanks for the help!!!

Just take out the smaller disk, install new system on the new one and use migration assistant to transfer data from the old one using some sata - usb...

I like Carbon Copy Cloner a lot from Bombich Software. It use to be free, but now they charge. It is excellent and if your hard drive fails you can put in a new one, clone from one to the other and be up and running in no time.

http://www.bombich.com/

I have recently started using TM but I am confused. It seems to be backing up everything on my computer, regardless of whether the file has changed or not. I have many files that have not been touched in ages.

Why is it doing this if indeed this is the case?

Time Machine is suppose to copy just files that change, and for files that have not changed, it will link to a previous unchanged version so that the Time Machine view of your backup looks like everything on your file system, but any given snapshot mostly contains a few recently changed files and most of the other files displayed are from a previous snapshot when the file really changed.

So the list of files shown in any given backup are not the actual files TM has backed up, except for those that have changed?

If you are talking about using the Applications -> Time Machine application to view your backup which shows the layers (snapshots) of backup, then yes, each snapshot contains real files that have changed, and links to previous snapshots where the file was last changed. If the file never changes from when you make your first Time Machine backup, then the links go all the way back to that copy.

If you are looking at a different list, you would need to specify what that list is.