1 Reply Latest reply: Jun 18, 2013 5:14 PM by kostby
dunks71 Level 1 Level 1

Hi everyone,



My main HD is becoming full and I need to free up at least 100Gb, If I have my working HD backed-up on my Time Machine then theoretically can I make free space on my working HD by deleting the originals?


And then time machine should have a copy when i need it?


Make sense!





iMac, Mac OS X (10.6.8), Time Machine
  • kostby Level 4 Level 4

    Welcome to Apple Support Communities. We're all users here.


    Unfortunately, that's not the philosophy used to design Time Machine backups.


    In theory, your idea is good for a while if your Time Machine drive is gigantic (say 10 times the capacity of your current internal storage, 1TB per 100GB internal storage).


    There is no guarantee that you'll be able to retrieve Time Machine backups 'forever', because when the Time Machine drive eventually gets full, it removes the OLDEST backups to free up additional space, and notifies you AFTER those backup files were erased.


    Time Machine is mostly focused on having recent backups. It copies changed files to the Time Machine drive  hourly for the last 24 hours, then grooms those backups daily, weekly, and monthly. Details supplied by Apple here > http://support.apple.com/kb/ht1427


    So yesterday's spreadsheet and last week's report and last month's vacation photos will be there for quite a while, but six months, a year, two years, three years from now, as your Time Machine drive fills up and old files are deleted to make room for new files, there's no guarantee, especially if you are frequently adding/changing/deleting files from your internal drive.


    You didn't ask, but paranoia about having enough backups and being able to access them when you NEED them comes from experience. If you want to be (relatively) certain that you can retrieve files you've removed from your current drive, I suggest a multi-step backup strategy.


    1) Clone your entire current hard drive to another external hard drive of at least equal capacity on a regular basis (weekly, monthly, What's your time worth?); That gives you a bootable backup of the most recent stuff in case your primary drive fails. Then you can use Time Machine to quickly restore JUST the stuff you created since your last drive Cloning, instead of spending an entire day or more restoring a full Time Machine backup.


    2) Use cloud storage from more than one vendor. iCloud and iTunes is great, but also use free accounts from other providers, so in case of a catastrophic event affecting an entire region, you're safer, because at least some of your storage will be in another location.


    3) Burn DVD copies of priceless files such as family photos that can never be recreated by any means. Store them off-site, like a bank safe-deposit box. Keep a copy at work. Mail them to your relatives. Remember that technology keeps changing and today's DVD may be as useless as an 8-track tape or audio cassette in a few years, so keep up with the technology.


    4) Copy your own critical WORK files to flash drives and carry them with you if permitted by your company.


    3 or 4 (or 14) backups is still not an ABSOLUTE GUARANTEE that you'll always be able to retrieve a file later, but it's better than relying solely on Time Machine, and then discovering that the files were erased without warning.


    Message was edited by: kostby