Here are some questions and problems that people often encounter when using Jettison. Before consulting this list or contacting us, please make sure you are using the latest release of Jettison, version 1.8.5.

If you have a problem that is not addressed here or feel a question should be here but isn't, please send mail to

Jettison's icon in my menu bar is appearing as an outline. What's wrong?

The outlined icon means that Jettison's "Eject external disks before system sleep" feature is turned off. Turn on this checkbox to enable it:

I've installed Jettison, but I'm still getting "Disk ejected improperly" errors. Why isn't Jettison working?

Jettison is almost certainly ejecting your drives as it's supposed to, but there are some features in macOS that can still cause the error messages to show up.

The short answer: Turn off problematic sleep behaviors using this applet:

(it also provides a button to turn them back on if you change your mind). Note: Among other things, this disables the TCP Keep Alive mechanism when the sytem is sleeping. This will result in Find My Mac not updating its location when the system is asleep.

The long answer(s):

  1. The most common source of problems is the Power Nap feature in macOS ( What happens is that Jettison ejects your external drive when you put your computer to sleep, but your Mac wakes up later via Power Nap and tries to do a Time Machine backup. Time Machine attempts to write data to the drive even though it is not there, which causes the disk journaling system (part of macOS that ensures data on your disk doesn't get corrupted) to save the data so it can write it to the disk later. Then, when the computer wakes up and the disk remounts, macOS sees an inconsistency between the data in the disk journal and the drive, so it puts up the warning message.

    If you have a Mac that supports Power Nap, you can see if this is the problem by opening the Energy Saver preferences in System Preferences and turning off Power Nap. Note that if you're on a MacBook Air or MacBook Pro, you must turn off Power Nap in the "Power Adapter" tab of your Energy Saver preferences.

  2. MacBook models released after mid-2012 (and MacBook Airs after mid-2010) will enter "safe sleep" mode after being asleep for a specific amount of time. The transition from normal sleep to safe sleep can sometimes result in the "Disk ejected improperly" error message.

    You can disable safe sleep using the following commands in Terminal:

    sudo pmset -a hibernatemode 0
    sudo pmset -a autopoweroff 0
    sudo pmset -a standby 0

    For more information on safe sleep, hibernation, standby and autopoweroff modes, see this article: Apple also has its own Knowledge Base articles discussing standby ( and autopoweroff (

  3. In the Energy Saver pane in System Preferences, turn off "Wake for network access." That can sometimes cause your Mac to partially wake from sleep, resulting in "Disk ejected improperly" error messages even though the disk was ejected correctly.

    Note that this may still not be enough, as the Find My Mac feature may also periodically wake up the machine. To turn all "dark wake" features off, use this command in Terminal:

    pmset -a tcpkeepalive 0

    or download and run the applet given in the "short answer," above.

Jettison isn't remounting my password-protected external drive.

In order for Jettison to remount a password protected volume, the password must be saved in your Keychain. To set it up, manually mount the volume using Disk Utility, and when prompted for your password, click on the "Remember this password in my keychain" checkbox when you enter it. The next time Jettison attempts to mount the volume, you'll get a security confirmation to allow Jettison to access your keychain - grant it "always" access and then things should work.

I bought Jettison through the Mac App Store. Can I upgrade directly from your web site?

Yes, just download the latest version of Jettison here.

Before copying the new version to your Applications folder, however, please double-click it to run it once directly from the disk image. Jettison will make a copy of your App Store receipt (which is embedded in the Jettison application that you downloaded from the Mac App Store). You can then copy Jettison to your applications folder, deleting the version that you got from the Mac App Store.

If you've already replaced your App Store copy of Jettison without running it first, you'll need to backtrack a bit. Please do the following:

  1. Delete all copies of Jettison from your Mac.
  2. Open the App Store application and click on the Purchases tab.
  3. Find Jettison in your list of purchases and re-download it.
  4. Visit our website again and download Jettison from
  5. Click on the .dmg file to open it, then double-click on Jettison there.
  6. Copy Jettison from that window to your Applications folder.

Why can't Jettison eject one of my external drives?

This happens when an application is accessing a file on your external drive. Because the application will expect the file to still be there when your Mac wakes back up, macOS won't let Jettison eject the drive. To fix this, you need to determine which application is using the drive and either close the file(s) that are on the drive or quit the application completely. Jettison attempts to diagnose the problem and will let you know which files are open if it can determine that.

How can I stop Jettison from remounting drives when my Mac wakes up?

  1. Select "Preferences" from Jettison's menu in the menubar.
  2. Click on the "Extras" tab.
  3. Turn off "Remount drives upon wake-up".

If you want to prevent just a single drive from remounting, you can add it to the "Don't remount these disks..." list in Jettison > Preferences > Extras.

Can I control what Jettison does with one specific disk or device?

Sure. Choose "Preferences" from Jettison's menu in the menubar, then click on the "Extras" tab in the preferences dialog. You'll see this:

You can choose drives from the "Also unmount internal disks", "Don't unmount external disks" and "Don't remount these disks" menus to fine tune what you want Jettison to do.

Jettison ejects my drives when I put my Mac to sleep manually, but not if it sleeps due to being left idle.

In many cases, this is due to the fact that your Mac, when left idle, isn't actually going to sleep - it's just turning the display off. This can be caused by a number of things, most often some software or hardware that explicitly prevents macOS from entering sleep mode. You'll have to determine which application is keeping your Mac from sleeping - the easiest thing to do is to run the Terminal application and enter this command into it:

pmset -g assertions

Look for the string "PreventUserIdleSystemSleep" in the output - the application that made the request should be listed at the beginning of the line.

Jettison will not start up. It keeps saying it needs to install its helper application and asking me for my administrator password.

This happens when another application has installed a helper app into the folder "/Library/PrivilegedHelperTools/" and has given the folder the wrong security permissions.

The easiest way to fix this is to download an AppleScript we've created called "Fix PrivilegedHelperTools permissions". You can get it by clicking here. Just unzip the script application, double-click it, and type your administrator password into the dialog box that comes up. After doing so, you should be able to launch Jettison and install its helper application successfully.

How do I uninstall Jettison?

Just open your Applications folder and drag the Jettison application to the Trash.

If Jettison has installed its helper application, you can also remove that too, though it's not necessary to do so - the helper will never run once you remove the Jettison application from your computer. To remove the Jettison helper app, just locate and throw this file into the Trash:


or just download and run this AppleScript applet:

Note that in either case you'll need to enter your Mac's administrator password to remove the helper app.


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System Requirements
macOS 10.9 through 13.0
Runs natively on Intel & Apple Silicon

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