Get Mac OS X to Stop Asking to Use New Disks for Time Machine

Jun 22, 2016 - 8 Comments

Time Machine in Mac OS X All Mac users should setup Time Machine backups with an external hard drive, Time Capsule, or network drive to insure they have regular automatic backups made of their stuff and MacOS X installation. But once you have a backup drive established with Time Machine, or if you use a different backup approach entirely, you may no longer want to be asked if you’d like to setup a new hard disk as a Time Machine backup volume each time you connect a hard drive to the Mac.

To be clear, we’re talking about what happens when you connect a new blank hard drive to a Mac, which will trigger a dialog box that asks “Do you want to use (drive name) to back up with Time Machine?” with a “Use as backup disk” or “Don’t Use” option. This is the dialog request we are aiming to disable here for connecting new drives to the Mac. What we’re going to cover will not disable Time Machine, it only disables that pop-up backup disk request dialog box in Mac OS X.

Average users should keep this dialog enabled and should not mess around with defaults command strings or the command line, this is intended for advanced Mac users only.

Disabling Time Machine Use New Drive Setup Requests in Mac OS X

  1. Open Terminal from /Applications/Utilities/ and enter the following syntax:
    defaults write DoNotOfferNewDisksForBackup -bool true

  2. Hit Return for changes to take effect, exit out of Terminal when finished
  3. Connect a new hard disk drive to the Mac, OS X will no longer display the “Would you like to setup Time Machine?” screen

Again, this does not disable Time Machine, and it does not impact existing backups, it only stops the pop-up window from showing up. This can be very helpful for Mac users who rely on something like SuperDuper, BackBlaze, Crashplan, CarbonCopyCloner, or another backup solution, who do not want the Time Machine setup requests to appear.

Re-Enable Time Machine New Disk Backup Requests in Mac OS X

If you want to undo this and return OS X to it’s default behavior of asking to setup Time Machine each time a new disk is attached to the Mac, simply using the following defaults command string:

defaults write DoNotOfferNewDisksForBackup -bool false

Again, hitting Return will cause changes to take effect. In this case, the Mac will return to the default behavior of offering to use the new disk as a Time Machine backup drive.

Regardless of how you have this setting configured, you should always backup the Mac on a regular basis. Setting up Time Machine for automatic backups on a Mac is easy and a great choice for most users. Whatever you do , don’t skip creating back ups, they’re important.


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Posted by: Paul Horowitz in Mac OS, Tips & Tricks


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  1. digipass says:

    Thanks for this great tip!

    Obviously Time Machine sucks compared to alternative paid-for solutions.
    Naive non-technical users through the years have obliterated existing disks, because they answered yes to using a disk with content on it, without understanding the consequences or just inadvertently. I blame Apple bad design for this.

    For some lazy users not wanting to check out the competition, TM can be a solution and it’s much better than nothing, if it only would on default shut up about new disks being added.

    With automated backups off and with NO previous archives being TM just suggested in macOS 10.14 to “take over” my existing backup disk that I use another paid-for solution on. No thank you, Apple. Get out of my face.

  2. Rakib Akramujjaman says:

    dear sir,
    my mac is loading when I did this switch on.

    after loading then its off.

    so what is this problem..?
    do you tell me pls

  3. Jim Roberts says:

    Time Machine works well for me. I have a dedicated, separate drive for it. It has saved my butt a couple of times. Usually only do one or two backups/ day and eject it so I can just take my MacBook Pro and go when I want.

  4. no way says:

    Time Machine is a joke, always has been. First off it’s way overkill for the average consumer, incremental backup via cloning with SuperDuper or CarbonCopyCloner is a much more usable method, allowing direct access to the backup drive for easy file retrieval and no ever growing backup that saves every little change you make as a new file.

    Everyone I know that has used TM has had issues resulting in the loss of their backup. My regime of Superduper requires at the end of the day, I plug in my back up drives, in the AM my computers have been powered down and all my data saved to directly BOOTABLE drives. Try doing that with TM without tearing your hair out.

    • PH says:

      Time Machine works fine for most Mac users and it’s by far the easiest backup strategy to implement for most. I do prefer SuperDuper and CCC for true accuracy and replication but they’re much more advanced in comparison to simple ™ backups.

  5. mark says:

    Since Snow Leopard, I haven’t been able to get Time Machine to run for more than three months before it just stops. I have a good automated backup regimen that keeps daily, weekly and monthly copies of my system, and regular daily copies of my external data drives. There’s a lot of redundancy, but I wish I could get Time Machine to work reliably.

    Any suggestions?

    • Doug says:

      Time Machine works fine if the drive has enough space and you’re on a new Mac version. But, Snow Leopard is a seven year old operating system, it still works well for some users but to get new features and bug fixes you need to update to newer versions of Mac OS X. Mavericks is a good compromise if you want to avoid the fluff of Yosemite and El Carpitan.

      • mark says:

        I think you misunderstood me. Time Machine worked up until Snow Leopard and then the reliability problems kicked in. I haven’t stopped upgrading hardware or OS X. I usually try Time Machine on a new OS installation and it has only worked for a few months before stopping. It’s now stopping on 10.10.5 on a year old MBP. It’s always given a drive twice the size of the source drive so that isn’t the problem.

        I’ve been using SuperDuper for ages and have added CCC for things SD can’t do and they’ve been utterly reliable.

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