Showing posts with label OS X El. Show all posts
Showing posts with label OS X El. Show all posts

Tuesday, May 3, 2016

How to Secure Erase Free Space on Mac Drives with OS X El Capitan

Erase free space on a Mac drive from the command line
Many Mac users running a modern version of OS X El Capitan have noticed the Secure Erase Free Space feature has gone missing from Disk Utility. What the “Erase Free Space” feature did (and still does in prior versions of Mac OS X) was overwrite the free space on a drive to prevent file recovery, adding a layer of security and privacy to file removal, much in the way that Secure Empty Trash performed a similar function of overwriting data after removal.

For those wondering, these features were removed from the modern version of Disk Utility in Mac OS X because they do not work on SSD volumes, which are becoming more commonplace and nearly all Mac laptops ship with them by default now. But not everyone has an SSD drive, and thus some users may still wish to perform a secure erase of free space on their Mac hard disk. To achieve the same secure erase in modern versions of Mac OS X you’ll need to turn to the command line. And yes, this works to erase free space on older versions of Mac OS X too, but since they can do the same task with Disk Utility it’s perhaps a bit less relevant to the prior releases.

This is for advanced Mac users only who are comfortable with backing up their Mac, using the command line with exact syntax, and the concepts behind permanently removing data. To be perfectly clear, this secure erases only the free space on a drive, aimed at preventing file recovery efforts, it does not perform a secure erase of the entire hard drive as described here.

How to Secure Erase Free Space on Mac OS X El Capitan Drives via Command Line, Without Disk Utility

Back up your Mac before attempting to use these commands. The command line requires precise syntax and is unforgiving, improper commands could lead to the unintended removal of data you do not want to delete, permanently, as this is a secure erase function. You have been warned, so backup your Mac data first, then proceed at your own risk.
To get started, launch the Terminal (found in /Applications/Utilities/) and use the following general syntax, replacing level and drive name as appropriate:
diskutil secureErase freespace (level 0-4) /Volumes/(Drive Name)
(level 0-4) is a number indicating the number of passes to write to the free space, ‘freespace’ indicates you are erasing only the free space and not the entire drive itself – a critically important difference – and (Drive Name) is self explanatory. Users can also choose the disk identifier if desired. If you aren’t sure of the name of the drive, using diskutil list will show you all mounted drives and partitions. If the drive in question has a space in the name, you should place it in quotes or escape it with backslashes.
For example, to perform a secure erase with 35 passes on free space on a drive named “Macintosh HD” you could use the following command string:
diskutil secureErase freespace 3 "/Volumes/Macintosh HD"
Hitting return will instantly begin the secure erase of any free space. This is irreversible, so as we’ve mentioned a dozen times already, be sure the syntax is exact.
Secure erase free space on a Mac hard drive from the command line
The manual page entry on diskutil offers the following details on the secure erase feature, detailing the level of writing over free space.
secureErase [freespace] level device
Erase, using a secure method, either a whole-disk (including
any and all partitions), or, only the free space (not in use
for files) on a currently-mounted volume. Erasing a whole-
disk will leave it useless until it is partitioned again.
Erasing freespace on a volume will leave it exactly as it was
from an end-user perspective, with the exception that it will
not be possible to recover deleted files or data using utility
software. If you need to erase all contents of a partition
but not its hosting whole-disk, use the zeroDisk or randomDisk
verbs. Ownership of the affected disk is required.
Level should be one of the following:
o 0 – Single-pass zero-fill erase.
o 1 – Single-pass random-fill erase.
o 2 – US DoD 7-pass secure erase.
o 3 – Gutmann algorithm 35-pass secure erase.
o 4 – US DoE algorithm 3-pass secure erase.
That’s all there is to it, and this is how you can continue to erase free disk space on a Mac running OS X El Capitan or later with the newly limited Disk Utility. Another option is to use an old version of Disk Utility in modern versions of Mac OS X, either from a boot drive or recovery mode, of an older Mac OS release, or with the application itself, but that is generally not recommended.
And yes, this works on both standard hard disk drives with spinning platters, and modern SSD disks, though with an SSD drive the feature is less relevant as TRIM / garbage collection should handle the file removal on it’s own. For SSD volumes, a better option is to enable and use FileVault disk encryption on the Mac, which encrypts data on the drive making it unrecoverable without the FileVault key, thus obviating the need to securely erase free space on the volume.
Know of any other helpful secure data removal tips or tricks, or another way to securely erase your free disk space in modern versions of Mac OS X? Let us know in the comments.

Source Url and Image: How to Secure Erase Free Space on Mac Drives with OS X El Capitan
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Thursday, April 14, 2016

How to Remove a Disk from Time Machine on Mac

Time Machine in Mac OS X All Mac users should have regular automatic backups setup with Time Machine, it’s easy to use and ensures that your personal data and entire Mac is recoverable in the event something goes wrong with the computer. Some people go even further and setup redundant Time Machine backups with multiple disks for added data protection. But sometimes you may decide a particular disk drive is no longer needed by Time Machine, and thus you’d like to remove that particular drive from the backup process without disabling all other Time Machine backups. This can be easily done, and all it does is stop backing up to the particular drive in question, it does not turn off Time Machine to other volumes, and it does not delete any of the backups on the removed drive.

Deleting a Hard Drive from Time Machine Backup to Stop Backups to That Drive from a Mac

Note that you do not need to have the drive connected to the Mac to remove it from Time Machine, this process is the same in all versions of OS X:
  1. Pull down the  Apple menu and choose ‘System Preferences’
  2. Go to the Time Machine system preference panel, then scroll down in the drive list to find “Add or Remove Backup Disk” and click that
  3. Click to remove a Time Machine drive
  4. Select the hard drive, disk, or backup volume that you want to remove from Time Machine backups, then click on “Remove Disk”
  5. Select the drive to remove from Time Machine backups
  6. Confirm that you want to remove the drive from Time Machine and stop backing up to the disk in question
  7. Confirm to remove the drive and stop backups to that particular volume from Time Machine
  8. Exit out of System Preferences when finished
The removed drive will no longer be part of the Time Machine backup chain, meaning when it’s connected to the Mac it will no longer trigger the automatic backup process. Additionally, manually started Time Machine backups will also no longer go to the removed drive when it is connected.
Again, this does not delete any of the data from the Time Machine drive, it simply stops backing up to the drive that has been removed. This also does not turn off Time Machine.
If you want to, you can remove the actual Time Machine backup files from the drive in question yourself, or even format the drive to be Mac compatible and wipe it completely clean of any other data. There’s also nothing wrong with leaving the files there if you think you’ll need it again down the road or refer to them in the future.
Regardless, you’ll want to be sure you have some form of backup going to Time Machine or to another service, never let your Mac or iOS devices go without backups!

Source Url and Image:  How to Remove a Disk from Time Machine on Mac
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Tuesday, April 12, 2016

How to View Live Photos in Messages for Mac

Play Live Photo in Messages for Mac
Live Photos are basically a still photo that comes to life as a short video, they’re a neat feature that can be captured by newer model iPhone cameras, and now the Messages app on the Mac can view these little moments if they’re sent your way.

To have access to Live Photos in Messages for Mac, you’ll need to be running OS X 10.11.4 or later, as earlier Messages versions don’t support the feature in OS X. Aside from that, you’ll just need someone with an iPhone that can take Live Photos to send the Mac one, the rest is pretty simple.

Watching Live Photos in Messages for Mac OS X

  1. In the Mac Messages app, open the message where the sender has sent you a Live Photo, the Live Photo can be indicated by the little icon in the upper left corner of the image
  2. A Live Photos is indicated by the little icon in the upper left corner of the picture
  3. Double-click on the Live Photo within Messages app to open a preview window of the picture, the live video portion will immediately play
  4. Playing a Live Photo in Messages for mac
  5. Re-play the Live Photo by clicking the little “Live” button in the lower left corner of the preview image
  6. Live photo button
Simple, easy, and works with any Mac with a compatible version of Messages app.
You can try this out yourself if you don’t have someone sending you Live Photos constantly, all you need to do is take a Live Photo with an iPhone camera and then send it to yourself via Messages in iOS so that you can view it on the Mac in the Messages client.
This is a nice feature addition to Messages for Mac, since previously the Live Photos either had to be imported into the Photos app or the sender would have to convert the Live Photo to an animated GIF before sending it over to get a similar experience (for the record, I still hope a ‘convert to gif’ option arrives in future iOS versions, but anyway…).

Source Url and Image:  How to View Live Photos in Messages for Mac
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How to Change the Default System Font in OS X El Capitan to Lucida Grande

Change the Default System Font in OS X El Capitan to Lucida Grande
The Lucida Grande font is known for its crisp and obvious readability which makes it a great user interface font, and it rightfully served as the Mac OS X default system font for many years. Then along came Yosemite, where the Mac system font was changed to the generally unpopular Helvetica Neue. Apple has since improved font readability considerably by changing the default system font yet again in OS X El Capitan, this time to a new font called San Francisco. While the San Francisco font is considerably better as a display font than Helvetica Neue, it’s still not quite as readable for some Mac users and on some non-retina displays as Lucida Grande. Fortunately, with a little effort you can change the default system font on a Mac with OS X El Capitan to Lucida Grande again, and return to the classic user interface font.

This app changes the system font, used in menu bars, menus, the Finder, Dock, window title bars, and elsewhere. If you like the system font the way it is now, or don’t even care, you likely won’t benefit from this application.

Replacing the Mac System Font in OS X El Capitan to Lucida Grande (from Mavericks)

  1. Consider starting a backup of the Mac with Time Machine and waiting for it to finish if you haven’t done so in a while, it’s unlikely you’ll have any problems but backing up is good practice anyway
  2. Go here to download the El Capitan Lucida Grande app, it’s free and open source if you feel like poking around the code yourself
  3. Right-click (or Control+Click) on the “El Capitan Lucida Grande.app” file you just downloaded and choose ‘Open’ – this will launch the app beyond Gatekeeper
  4. Choose the “Patch & Install & Clear font cache” button in the launcher app, then enter the administrator password when requested, the admin login is necessary to create a new file in the /Library/Fonts/ folder, which is the system level font directory*
  5. When finished, quit out of the app and reboot the Mac for changes to take effect throughout OS X
When OS X reboots the system font will be changed to Lucida Grande from San Francisco. Here’s a before and after shown as animated GIF, the change is subtle:
Replacing the default system font in OS X before and after
Here’s a still before and after as well, this is what a Finder window and menu bar look like in OS X with the default San Francisco font (the before):
OS X El Capitan default system font of San Francisco
And here is what the same Finder window and menu bar look like in OS X with Lucida Grande font (the after):
OS X El Capitan with Lucida Grande
As you can see, the changes are extremely subtle. This animated gif gives you an idea of just how subtle the change is, with Lucida Grande being ever so slightly bolder, slightly wider, with slightly more spacing, with the result being it’s slightly more readable to some individuals.

Looks Interesting, But How Does this App Replace the System Font?

For those who might wish to understand what this app is doing to replace the system font in OS X: it’s quite simple, the “Lucida Grande El Capitan” app works by creating a new patched version of the Lucida Grande font and placing that system font file in /Library/Fonts/ called “LucidaGrande_modsysfontelc.ttc”. In other words, it’s simply creating a new font file that is recognized by OS X as being the default system font, thus when Mac OS X boots it loads that new system font file version of Lucida grande rather than San Francisco — it does not replace or modify any system files.

The Default System Fonts Are Barely Different? What’s the Point?

Indeed, going from San Francisco to Lucida Grande is much more subtle than abandoning Helvetica Neue for Lucida Grande or for Comic Sans, so if you’ve never thought twice about the system font in OS X El Capitan let alone in Yosemite or Mavericks, you probably won’t even notice the change, meaning this isn’t really aimed at you. But, for users who either just prefer Lucida Grande due to longstanding habit, or because it’s easier for them to read on a particular display, this little unofficial font patch is a nice modification to Mac OS X.
Perhaps in the future Apple will introduce a ‘bold fonts’ option in OS X Accessibility preferences to make default font text easier for some Mac users to read, much like the bold fonts choice in iOS. But that hasn’t happened yet, so in the meantime, if you’re not thrilled with the system font in OS X El Capitan, consider changing that system font back to the classic Lucida Grande, because for many it’s just easier on the eyes and easier to read.

A few known font display bugs

Indeed there are a few text kerning and spacing bugs with the initial release patch, presumably a fix will resolve those issues shortly. The most annoying is likely found in Safari where multiple tabs start squishing the text together in a tab title, here’s what it looks like:
font bug
Again, a future release of the Lucida Grande replacement font will likely resolve that issue. If it’s a dealbreaker, just uninstall it and wait for the time being.

What About Changing the Default System Font to a Different Font?

If Lucida Grande isn’t your thing, there are other options for new default system fonts in OS X El Capitan which use the same basic idea as this app, many of these existed for prior OS X releases but have yet to be modified for El Capitan. Currently, other alternatives are:
* Note that you can also install fonts and modified Mac system fonts in the user fonts folder at ~/Library/Fonts/, but doing so sometimes causes weird font display gibberish that isn’t remedied by dumping font caches in OS X, particularly with dialog and alert windows. Thus, if you’re replacing the system font, go with the root font directory.

Source Url and Image:  How to Change the Default System Font in OS X El Capitan to Lucida Grande
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