This question serves to share and collect the enhancements which are not documented by Apple, or documented poorly.

Please justify your answer; if it is something that is well documented by Apple and elsewhere on the web, it does not belong here. Your answer should put the feature into context, explaining how to use it. Add a picture if necessary.

Please add only one topic per answer. Try to find and edit existing features / answers rather than posting a duplicate answer which will end up getting deleted. Note that answers which are not specific to Mountain Lion will be removed as well. You can post such answers here.

  • 27
    I wish I had enough rep on Apple.SE to downvote. As it is, you'll have to make do with an angry glare: ಠ_ಠ – Buns Glazing Jul 25 '12 at 18:47
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    I'm sorry, I just think it's not a very good question for the Q&A format of the site. No amount of editing will change that, in my opinion. – Buns Glazing Jul 25 '12 at 18:51
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    @GnomeSlicE We've done these type of wiki collections several times in the past. While they are disputed, they always receive a lot of resonance. It's better to avoid them, especially for little things. But as Apple does not document everything they introduce in their software this question can be useful to many. Feel free to discuss these type of questions on meta. – gentmatt Jul 25 '12 at 18:54
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    Disagree with GnomeSlicE. Agree with gentmatt. These types of questions, when well cultivated, can be very useful and discourage (to some extent) the really bad CW posts. – daviesgeek Jul 25 '12 at 19:02
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    The 200+ improvements mentioned by Apple can be found at apple.com/osx/whats-new/features.html – Hope4You Jul 25 '12 at 19:12

53 Answers 53


Safari Tab Sharing:

If you have more than 1 Mac signed into the same iCloud account, then you can access a list of any open Safari tabs on your other machines by clicking the button in the toolbar as follows:

enter image description here

So far so yeah yeah we all knew about this months ago, but:

Start: Previously undiscussed material

In addition to opening the tab it even captures certain state definitions, such as whether or not you have the page open in Reader mode or not (and opens the tab to match accordingly). In reader mode on the remote tab? You will be if you open it locally via iCloud tab sharing.

Also things like dynamic page titles are carried over such as the (1) that appears when a new question with activity is identified on this site for example Have an open but unattended SE site tab open? You'll be able to see how many new questions with activity just by watching the tab title change. Same thing applies to Facebook chat windows etc, anything that alters the page title without you needing to navigate elsewhere in order for it to do so.

To open the shared tab in a new tab rather than replace the contents of the current one, simply Command+Click it

End: Previously undiscussed material

When iOS 6 is released, the same features will be available cross platform between Safari and Mobile Safari.

  • Ho ho ho, comedy downvoter :) – stuffe Jul 26 '12 at 20:42

Mountain Lion removed the option to show the estimated battery time remaining from the battery menu bar item.

This data can still be accessed if your battery is not fully charged and isn’t charging, though. In those cases, + Clicking the battery icon in the menu bar shows something like this:

  • Finally! That was such a deceptive feature lol – Alexander - Reinstate Monica Jul 28 '12 at 4:49
  • 3
    Oops ... I relied on this feature. – njahnke Jul 28 '12 at 16:27
  • The option is still there but you must now ⌥-click on the battery status: this will show the estimated time at the top of the dropdown. – Wichert Akkerman Jul 29 '12 at 20:41
  • @WichertAkkerman Doesn’t work for me. All I see is this: i.imgur.com/jFGZ2.png – Mathias Bynens Jul 30 '12 at 7:43
  • 1
    @MathiasBynens That's because your battery is already fully charged. Try discharing it a bit and then check again. – Wichert Akkerman Jul 31 '12 at 10:25

Ask to keep changes when closing documents

You can now force Mountain Lion to ask whether you want to keep changes you made to a document when closing it, which effectively allows you to sidestep autosaving.

System Preferences > General > [] Ask to keep changes when saving documents

Clearing the checkbox, as shown below, allows unsaved changes to be saved automatically.

enter image description here

  • 1
    Please try to avoid bloating answers. I think in this specific case the picture wasn't necessary. – gentmatt Jul 25 '12 at 21:30
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    I think having a nice screenshot for each one would be nice, in order to get TL;DR type people up to date in a quick skim through the page – Alexander - Reinstate Monica Jul 25 '12 at 22:12
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    Whoever downvoted this : you are wrong. The "Close windows when quitting an application" was there in Lion, but not this. – houbysoft Jul 26 '12 at 2:48
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    @houbysoft I totally agree, and I think this is a terrific change, but then that's exactly what your tip should say. Don't say you can disable autosaving; you can't. Be accurate. – matt Jul 26 '12 at 21:08
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    @GrahamPerrin The answer is still inaccurate. I repeat, you cannot avoid automatic saving. At close time, the document changes have already been automatically saved. Regardless of the wording of the checkbox or the dialogs, what's happening is only that you are alerted to this fact so that you can revert if you like (using the Versions feature). That is something you could have done anyway. So the alert is all that is new. It's good, but you are not in fact avoiding / allowing automatic saving; it's happening, regardless. – matt Aug 7 '12 at 17:24

Document auto-locking removed!

In Lion, an auto-saved document would automatically lock itself after two weeks of inactivity. (This time interval could be adjust thru a pref hidden deep in Time Machine.) In Mountain Lion, this "feature" has been quietly removed; no more auto-locking.

  • 3
    Could you please change the tone of this post to something less ranty? – Jason Salaz Jul 26 '12 at 19:27
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    Or just delete your answer and win the Peer Pressure badge like I just did :) – stuffe Jul 26 '12 at 20:41
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    It's an important change that has not been advertised by Apple, so it answers the original question. And the tone is right too; this was a bad Lion feature and annoyed everyone, so it's good that in Mountain Lion they withdrew it. – matt Jul 26 '12 at 21:11
  • @matt: Your second sentence is subjective--I for one used this feature quite often. – Matt Aug 1 '12 at 11:05

Quickly Renaming Bookmarks in Safari

When you click and hold on a bookmark on the Safari bookmark bar you can quickly rename it.


Documents in iCloud

If an application is iCloud-savvy, its Open dialog has an iCloud tab. You can not only open documents here, but you can also drag documents into the cloud from the Finder, and you can create folders (drag one document onto another to do so).

enter image description here

  • This open dialog is very good, but the save dialog with iCloud is downright stupid. – Jonathan. Jul 27 '12 at 10:17
  • Note that you can only access iCloud documents from the app that they were created/saved in. For example, Word won't be able to open a .txt file you created in TextEdit. – Matt Aug 1 '12 at 11:06

Quick access to Accessibility settings

Press ++F5 to bring up a new Accessibility Options window that offers quick access to a subset of the settings from the Accessibility prefpane.

enter image description here

  • 1
    Nice find! I wish that Apple would also include an option to toggle dictionary or location services here. – gentmatt Jul 30 '12 at 12:49

Reading List caches content for offline use

Reading List in Safari is not new (it was introduced in Lion). But in Mountain Lion, a Web page stored in the Reading List stores the page, not just the URL, so you can read the page later without having to download it from the network.

  • Should have been like that from the beginning. I mean, seriously: The Reading List in Lion was just a hall of fame for bookmarks. – gentmatt Jul 30 '12 at 12:46

Multiple Time Machine Backup Destinations

In Time Machine you can now select multiple backup destinations.

enter image description here

That was from the "OS X Mountain Lion Core Technologies Overview".

You can select additional disks from System Preferences:

enter image description here

  • Unfortunately, the UI for this is somewhat broken. Most importantly, the menu bar no longer shows when the last backup was taken (it shows only the last backup and status for one of the drives). – Thilo Aug 6 '12 at 10:12
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    Re: broken UI: 10.8.1 has improved this. Now it does show when the last backup was taken, even if it was to the "wrong" disk. – Thilo Sep 4 '12 at 1:50
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    Re: improved in 10.8.1: Maybe not, after all. – Thilo Sep 25 '12 at 10:01

Kernel Exclusively 64-Bit

"Starting with Mountain Lion, OS X exclusively uses a 64-bit kernel, but it continues to run both 32-bit and 64-bit applications (OS X Mountain Lion Core Technologies Overview)"

Why this is a good thing:

There are two reasons this is a good thing. The first is simple: 64-bit computing is necessary if you want one of the programs on your computer to have access to more than 4GB of RAM. Second, there are some speed boosts associated with running in 64-bit mode. The Intel processors that power Macs have built-in math routines that operate more efficiently in 64-bit mode, processing tasks in fewer steps. That means that certain math-intensive tasks will see a speed boost under Snow Leopard’s 64-bit applications (Macworld).

However, having a 64-bit kernel does have its downsides: some older 64-bit computers like the iMac (pre-Mid-2007), Macbook Pro (pre-Mid-2007), Mac Pro (pre-2008), and others are not able to run Mountain Lion. This has to do with the fact that now with Mountain Lion, Macs can only boot into 64-bit mode, but prior to that, Macs could boot into both 32 and 64-bit mode, so older Macs were able to boot into 64-bit mode, but their EFI firmware was 32-bit and therefore can only interface with a 32-bit kernel.

  • Note that almost all of the benefits were/are already available with the 32-bit kernel of OSX, and Lion already booted into a 64-bit kernel by default if supported by the hardware. (The hardware that didn't support it is the same hardware that Mountain Lion now fails to boot on) – pmdj Aug 7 '12 at 8:38

When updating apps, Mac App Store reopens apps and offers to skip open apps

When Updating All in the Mac App Store, rather than going straight down the list and demanding you shut down each open app along the way, it offers to let you skip the apps that are running:

enter image description here

Even better, if you do let it close an app, it will automatically reopen it when the update is complete. Furthermore, once you have initiated the update, the apps that are going to be changed are locked and a helpful error message is presented from the App Store if you try to launch an app that is about to be (or in the middle of) being updated. All together, these make updating apps less prone to error or conflicts due to files being in active use during an update.


You can quickly get rid of a notification by hovering over it and swiping with 2 fingers from left to right (swipe it off the screen)

And if you just want to peek behind it or something you can click and drag it (one finger) to the left and when you let go it will bounce back.

  • If you drag it further to the left, it will stick in that position until you drag it back. Useful if you need to access a control behind the notification, but don't want to actually dismiss it. – daGUY Nov 14 '12 at 20:23

Zoom and Mission Control/Launchpad play nice!

Finally, if you zoom in your screen (for example, by +scrolling), activating Mission Control or Launchpad doesn't immobilize the viewport!


Improved Kernel Security (ASLR)

"Apple introduced randomization of some library offsets in Mac OS X v10.5 (released October 2007). Their implementation does not provide complete protection against attacks which ASLR is designed to defeat.Mac OS X Lion 10.7 has improved ASLR implementation for all applications. Apple explains that "address space layout randomization (ASLR) has been improved for all applications. It is now available for 32-bit apps (as are heap memory protections), making 64-bit and 32-bit applications more resistant to attack." Since OS X Mountain Lion 10.8 the kernel as well as kexts and zones are randomly relocated during system boot" (Address Space Layout Randomization).

This is beneficial in that it protects the user against the malware exploits that rely on fixed locations for some well-known system functions.

  • Why the down vote? – pasawaya Aug 1 '12 at 8:25

Navigate forward/back while viewing a PDF in Safari

In Safari, if you are viewing a PDF, you can now use your normal 2-finger swipe to navigate forward or back! (Previously, this would only scroll the PDF or jump between pages if you used 3 fingers.)

  • The shortcuts for going back and forward no longer jump to previously viewed pages either. – Lri Aug 1 '12 at 10:39

Software Updates Now Come Through the App Store

Whenever you get software updates, they now come through the App Store. You can check for updates like this (which opens the App Store):

enter image description here

Prior to Mountain Lion, software updates took place in a separate application that looked like this:

enter image description here

  • 3
    If my iLife apps are not from app store, what happens? – Enrico Susatyo Aug 2 '12 at 1:10
  • @EnricoSusatyo - You mean if they're from a disk? – pasawaya Aug 2 '12 at 1:35
  • Yes, or if I haven't updated my iLife '08 from Snow Leopard. – Enrico Susatyo Aug 2 '12 at 1:37
  • @EnricoSusatyo - Then the new version of Software Updates should work for you. – pasawaya Aug 2 '12 at 1:43
  • 1
    @EnricoSusatyo My fresh install of iLife '09 was updated via the App Store as well - even though I installed it using a CD i bought. – gentmatt Aug 2 '12 at 10:10

Click-and-hold to toggle Notification Center

Click-and-hold the Notification Center icon to show your notifications; once you release the mouse button, they'll hide. This also works if you've assigned a keyboard shortcut for Notification Center (press-and-hold the key, then release).


Browse through photos in screensavers via keyboard

In any of the various photo screensavers, you can hit the left or right arrow keys to manually navigate between photos.


Clipboard content is persistent through reboots

The clipboard is not cleared on shutdown. All data in the clipboard remains there even after a power cycle.


Take app screenshots without shadow

You can now take screenshots of apps without the shadow. Press ⇧⌘4 to enter screenshot mode, then press space to select a window, like normal. However, instead of simply clicking to take the screenshot, ⌥-click the window to take the screenshot without the shadow.

On the left is the default style of screenshot; on the right is the sans-shadow screenshot.

  • 1
    upvoted - thanks for doing the work to find this great answer a proper home. – bmike Oct 23 '13 at 19:29

Navigate through a PDF in Mail.app by scrolling the mouse while hovering over it

The need to open a PDF in Preview/Quickview just in order to see pages other than the first one, is now gone.


When Show contact photos in the message list is enabled, user image additions/edits from Contacts.app are updated immediately in Mail.app (not after relaunch, as in Lion)

enter image description here


In Mission Control, holding option will immediately show the + icon for adding a new desktop and X icons on each secondary desktop. You can then click these icons immediately, instead of hovering and waiting for them to appear after a delay.

  • Can you definitely confirm that this is new in Mountain Lion? I'm confident that this existed already in OSX 10.7 Lion. – gentmatt Dec 28 '12 at 8:06
  • I hadn't discovered this until Mountain Lion, but it's possible it was there in Lion and I never noticed it. I don't have a Lion installation anymore to test on. Still, even if it's not new, it remains an "undocumented" feature of Mountain Lion... ;) – daGUY Dec 28 '12 at 14:33

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