Updated on 2/10/2012: You can easily use the MacBook, MacBook Air, or MacBook Pro in what’s commonly called clamshell mode, when the laptop lid is closed but the machine is hooked up to an external monitor, keyboard, and mouse, effectively turning your portable Mac into a desktop. Doing this is easy, here’s how to get into clamshell mode on system boot and when waking from sleep.

Activating Clamshell Mode On System Boot

* Hook up your external keyboard, mouse, power supply, and display
* Boot your MacBook and once you see the Apple logo, close the machines lid
* Mac OS X will now continue to boot using the external monitor as it’s main display, and your laptop closed

Using Clamshell Mode When Waking from Sleep

* Be sure the external keyboard, mouse, power supply, and display are hooked up to the MacBook, MacBook Air, or MacBook Pro
* Put the machine to sleep and close the lid
* Keeping the lid closed, hit any key on the external keyboard to wake the MacBook/Pro from sleep
* Mac OS X will now use the external display as the primary monitor

Clamshell mode works in Mac OS X 10.7, Mac OS X 10.6.8, and before.

Important notes on running a MacBook or MacBook Pro with the lid closed in clamshell mode:
Both the MacBook and MacBook Pro use the keyboard as a way to aid in the dissipation of heat, keeping the machine in clamshell mode reduces the cooling efficiency so be sure that the MacBook/Pro has adequate ventilation otherwise. The ideal situation of running a Mac with the lid closed is to use a laptop stand or something similar that increases the airflow around the machine. Insuring adequate airflow will reduce the likelihood of the machine overheating. You may notice the fans on your machine running more often when the computer is operating with the lid closed.

Personally, I like to keep my MacBook Pro’s screen open so I can benefit from the increased productivity of dual monitors, I just turn the larger external display into my primary screen.

Image via flickr

When shopping around for an external monitor, I was asked “What’s the maximum resolution I can get out of my MacBook with an external LCD display?” by a friend of mine. Well the answer depends on which MacBook you have, what video card it has, and what type of video interface you’re going to use (DVI, VGA, DVI-I, etc) to power the external display.

MacBook’s with shared GMA video cards can drive an external display with a resolution of up to 1920×1200 via DVI , or 1600×1200 via VGA

Newer MacBook’s (unibody included) with independent graphics cards can drive external displays with resolutions up to 2560×1600 via dual-link DVI

Both newer and older MacBook’s will support extended desktop as well as mirroring, but note the older MacBook’s with shared GMA video will have a slight performance hit when driving an external display, this is mostly noticeable when doing graphics intensive processing but rarely a significant issue. Either way be sure to get the proper mini-DVI to DVI adapter for your MacBook and external monitor.

[ picture via RegEx.info ]

I frequently get asked about the purpose of .DS_Store files by Windows System Administrators who have a few Mac’s on their networks. Here is my explanation:

What is a .DS_Store file?

.DS_Store files are used by Mac OS X to store folder specific metadata information. They are created in every folder that Mac OS X Finder accesses, even network volumes and external devices. Folder level customizations are stored in the DS_Store file, things like custom icons, icon placement, icon size, window placement, list views, custom background pictures or colors, etc. DS_Store files are intended to be unobtrusive, which is why they have a . in front of their name, which indicates to UNIX file systems that the file is invisible. Most Mac users will likely never see a DS_Store file at all.

What happens if I delete the .DS_Store files?

If you delete .DS_Store files from the Mac folders, you will lose that directories folder specifics; things like icons, window placement, background pictures, etc, will be lost. While there is no significant harm (except losing the folder metadata) to deleting DS_Store files, unless you have a very specific reason to delete them, you should keep them in place since the Mac OS X Finder uses them. Deleting the files is really only necessary in some specific Windows+Mac shared networking environments.

Can I stop the DS_Store files from appearing on network drives?

Yes, by executing the following command in the Terminal:

defaults write com.apple.desktopservices DSDontWriteNetworkStores true

It is rather easy to stop .DS_Store file creation on network connections but it is rarely necessary, read for more information.

Do you come here often? How about subscribing to our RSS feed, or follow us on Twitter! Both feeds will give you up to date posts directly from OS X Daily, so check them out.

Subscribe to OS X Daily via RSS

mdworker is short for ‘metadata server worker’ and if you’re still confused don’t feel bad. mdworker is basically the core technology behind Mac OS X’s awesome search engine Spotlight, it spiders meta data from your Mac and its files and creates a readable index so that you can find things practically instantaneously via Spotlight (command-spacebar). Here are some common questions and answers regarding mdworker, inspired by my recent switcher friend Daryl, who tweeted me asking why mdworker is taking up so much CPU.

What is mdworker?

As mentioned above, mdworker is part of Spotlight, which is basically a search engine for your Mac (think Google but locally, for your own files).

mdworker is slowing down my Mac with 60% CPU usage!

Yes, mdworker will sometimes cause your Mac to be slow and have high CPU usage, this is totally normal. You should just let it run until it’s finished, and CPU usage will be back to normal.

How long does mdworker take to finish?

This is entirely dependent on the last time that your Mac filesystem was indexed and the amount of new files since indexing. If you just plugged in a loaded external hard drive, expect it to take a while. 15 minutes to well over an hour are not uncommon amounts of time for mdworker to run.

Should I kill mdworker? What happens if I kill mdworker?

No you shouldn’t kill mdworker, because it’s doing you a service by indexing your Macs contents. If you do kill mdworker, your Mac filesystem will not be completely indexed and it’s searchability will be greatly reduced until mdworker runs again and completes a full indexing. There is no serious problem with killing mdworker, it’s just not recommended.

How can I stop mdworker or disable mdworker?

Since mdworker is part of Spotlight, you’ll have to disable Spotlight to disable mdworker. Again, this is not recommended, but if you want to disable mdworker here’s a how-to guide:
How to Disable Spotlight

What about mds? Is this tied to mdworker?

Yes, mds is the parent metadata server that runs the child process mdworker, the two usually run concurrently. You can read specifically about mds and Mac OS for more information.

Reader Mathew Prairen asks a common question about opening files that has a remarkably simple answer:

“I have a few image files from my PC that Preview refuses to open, is there any way I can force Preview to open these images?”

If you want to force open any file with virtually any program, simply hold down the Command+Option keys while dragging the file onto the applications icon.

Whatever the application is will attempt to open whatever the file is. In some situations this will work just fine, forcing many image editors to open other image files generally works, as does text files into text editors, but attempting to force an image editor to load your perl script probably won’t work. Basically there is no guarantee the program will like the file you are forcing it to open, but it will try anyway, and this can lead to some unusual results or the display of nonsensical characters, or even an error message indicating from the application that the file type is invalid. Due to this, if you’re going to attempt to force an application to open a file, try to stick within the general genre of that which the originating file came from.

Updated: 1/29/2012 – this is confirmed to work with Mac OS X 10.7 Lion

Reader Adam Smith writes in with the following question: “I am a new Mac user, and I love OSX! I have a MacBook Pro 15″. I would like to know though, is there a way that you can lock a MAC? Like in Windows, you can hit the shortcut “Windows Key + L”. Is there something similar in Mac or is there a script you can write? It’s just so I can leave my Mac while its doing stuff, lock it, so that no one else can play around with it. Thank you for your time.”

Yes there is! Mac OS X doesn’t have an active workstation lock quite in the same manner as Windows, but you can still lock your Mac’s workstation and require a password for all users to access the machine. Here’s how:

Lock an active Mac OS X workstation

The easiest way to lock down your Mac is by using a screen saver and password protecting it. Here’s how in three easy steps:

Select a Screen Saver – First, you’ll need to select a screen saver to activate. Open System Preferences and click the “Desktop & Screen Saver” icon. Pick any screen saver.

Enable a Hot Corner – In the same preference pane, click on the “Hot Corners…” button in the bottom corner of the pane. Select a “Hot Corner” – where you want the screen saver to be activated by dragging your cursor into that corner.

Enable Password Protection – Now you’ll need to password protect your screen saver. Navigate back to System Preferences and this time select the “Security” icon. Ignore all the FileVault settings, about halfway in the pane there is a check box for “Require password to wake this computer from sleep or screen saver” – click the box next to it so a check appears.

Try it out – Now anytime you drag your mouse cursor into the activated Hot Corner, you will activate the screen saver, which requires a password to return to the desktop. Also, if your machine is put to sleep it will bring about the same password prompt.

To further secure your Mac workstation, you can also require a password on system boot. Doing so is easy, just check the Login Options under the Accounts preference pane. It’s pretty self explanatory but if anyone wants a full walkthrough let us know.

Hello all you loyal OS X Daily readers! Recently we have been receiving a large number of Mac OS X related questions in our inbox. Normally our staff would try and respond with an answer to the best of our knowledge. However, sometimes we get a question we absolutely do not know the answer to. We think it would be fun to run some of these by the many regulars who stop by the site. Please help us with the following question, and feel free to continue to email us with any Mac OS X related questions.

Greg Simon writes:

“First off, I’ve enjoyed the numerous tips and tricks posted by the knowledgeable folks at OS X Daily. I have something I think you guys might be able to help me with. Recently I found myself writing a journal, and as such I really want to find a way to password protect it so my inner thoughts don’t end up in the hands of the wrong person. Multiple people use my laptop and its not a good feeling knowing that anyone could just double click my text file of emotion and find out everything about me! All I’m looking for is a way to encrypt a file on a file-by-file basis, do you guys have any suggestions?”