Why do I only have 98 gb's of storage available on my new retina macbook pro?

First of all, drive manufacturers quote sizes in 10^9 (10 to the power 9) byte units. The operating system and utilities measure disk space in units of 2^30 byte units. A manufacturer will quote 128,000,000,000 bytes, but the OS treats a Gigabyte as 1,073,741,824 bytes rather than 1,000,000,000 bytes. This means the OS will see the disk as 119.2 GB instead of 128 GB.

Next, the index structure on the disk that supports the filesystem will take up a percentage of the disk. Then you have to allow for the operating system and any applications that Apple have included in the system. These could easily account for the 20 GB of space that you cannot account for.

I hope this helps.

Do remember that when you buy any type of storage medium (or device with storage), the advertised storage is never what you actually get.

Roughly 10-15% of that storage is permanently used up by the OS of the system as well as for the features of the drive itself. So a 128GB storage device will only have 100-110GB available. And then considering pre-installed applications, they could take up even more space.

It's not really caused by formating or by advertising tricks. It's caused by your buying teentsy-tiny storage of 128GB, and then you complain that it is too small. Well, sure it is too small. The only way now to make it useful is to replace it with larger storage. Buy this–> http://eshop.macsales.com/item/OWC/SSDA12K480/ It is 480GB to replace your almost useless original storage, plus an external case to use the original storage as backup storage.

I don't understand why people ask "Should I get the 128GB or the larger storage?" and when I shout "The larger is still not large enough! Get as much as possible!!!" people give the Best Answer to someone who says "You only need that teeny-weeny 128GB. It's enough!"

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because of formatting, you do lose some room in your hard drive. Depending on if you're formatting for mac, pc, how many partitions, etc. will determine how much room gets left out afterwards. Then after that, the software to run the machine takes up more room. After that, is what you see whats left and can use.