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How Do I Recover Space On SSD Hard Drive In My MacBook Pro?

I bought a 512gb SSD to upgrade my early 2011 MacBook Pro and the speed increase is fantastic. (The computer also has an i7 processor and 16gb of ram). Moving to the SSD has by far produced the most dramatic speed bump, infact when I went to a genius bar at my local Mac store they advised me this upgrade was only way to get the top performance so I went to online supplier Crucial and bought the SSD (prices are coming down for these SSDs).
Here’s the question. My personal data is about 312gb and naturally in Finder it shows me I have 200 gb free out of the 512gb SSD.
However, when I used a third party analysis tool (Daisydisk) it shows me that actually I am using up 370gb of my SSD. So it seems about 58gb of space on the SSD which is ‘taken up’ and not available to use. Is there a way to reclaim this space.
A second question, I have read that SSDs can have blazing speed when new but can slow down weeks later and I have also read that a maintenance protocol can rectify this and extend the life of the drive. Something called TRIM maintenance has been mentioned but it’s too complicated to understand for me. Any help welcome on the basis that I’m never going to go back to old fashioned hard drives. Thank you for the website and podcasts, the extra knowledge I’ve got from you over the last few years has enhanced my productivity on my Mac and given me a lot of enjoyment.
The SSD drive was erased and formatted as usual using Mac journaled (so before you ask it was clean with n othing on it to start with). I then installed OSX 10.8.0 Mountain Lion and then brought my user data over.

Comments: 4 Responses to “How Do I Recover Space On SSD Hard Drive In My MacBook Pro?”

    11 years ago

    Remember that Macs now use unused space on hard drives for various things. They do this in a smart way -- making sure the space is free for you to use, but isn't just sitting idle. Of course virtual memory is one way, and computers have been doing that for years. But Macs also now use them for Time Machine backups -- "Local Snapshots." See
    I'll bet that is what is happening. So when this third party tool tells you something different, maybe that (and virtual memory) is the difference. This doesn't mean that this is "not available for use," it just means it is being used wisely while you are not doing anything else with it. But perhaps the third-party tool doesn't understand that. Local snapshots are pretty new and I'd imagine they just look like other files to tools like that.
    As for "trim" maintenance, I don't know anything about it. I have an SSD in my MacBook Air, of course, and have never experienced a slow-down or have tried to do anything like that.

      11 years ago

      Hi. I have installed the Intel 520 series 480 Gb i my MacBook Pro, and I have solved the TRIM issue by applying a few commands in Terminal. The Mac will then take care of the SSD maintenance without any TRIM toolboxes etc. Read the following article:

    John M. Hammer
    11 years ago

    Here is an article which explains TRIM very well:

    However, I'd encourage you to not worry about the "wear" of your SSD. You are unlikely to suffer any significant loss of capacity or notice much slowdown over the common lifetime of your computer.

    11 years ago

    Thank you Gary, the explanation is helpful and once again I've learnt something valuable from you. And John I'm grateful to you for your reassurance that the SSD drive is unlikely see a performance loss within the first few years or so of its life. So that complicated TRIM stuff is irrelevant !

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