Target Mode

This feature, target mode, saved my life.

What is it?

Target mode is a working mode of the Mac that turns it into an external disc drive.

I recently bought a new Mac Studio, as my good old iMac 27″ mid-2011 was dead, or at least, wouldn’t boot. It keeps looping between the start Bong and a grey empty screen.

I have a good backup (Time Machine) as well as iCloud copy of my files. I feel comfy about this migration to the brand new Mac. However, what I thought was a good Time Machine backup revealed unrecognized on the new Mac. Migration Assistant wouldn’t find the data on the disk. Or did I not wait long enough, since it is a 4TB USB 3 drive with lots of data on it, and may OSX has to kind of make its mind.

So I installed the new Mac without a restore from Time Machine, just the iCloud connection. That’s already good, since my Desktop and Documents were rapidly sync’ed from the cloud. Excellent.

But some of my important files, such as secondary Photos libraries were thus missing.

Here comes Target Mode

By pressing the T key at boot, the (old) Mac would enter the Target Mode and share the internal drive(s) over the Thunderbolt or Firewire ports. Great!

Problem, on the iMac 2011, Thunderbolt is a Thunderbolt 2 connector and my new Mac Studio has Thunderbolt 4 ports (on USB-C connector). Fortunately enough, my wife uses also an iMac 2011 with the proper Thunderbolt 2 connector and I managed to access the files on my old iMac on my wife’s iMac. The old iMac “Macintosh HD” disk just mounts on the other iMac as an external drive and I can read all the files on it.

However when I tried to share the said drive over the network in order to access it from the new Mac Studio, no luck. The shared drive looks empty. Maybe again I did not wait long enough for the authorization of sharing be applied.

So I copied the files I needed from the old iMac to my wife’s iMac local drive (130 GB of files) and then copied them again over the network to the Studio. Thank you Target Mode!


I eventually bought from Apple an adapter Thunderbolt 3 (USB-C) to Thunderbolt 2 and it worked just fine: my old iMac’s drives mount on the Mac Studio, pico bello.

What to do when your iPhone storage gets short?

Recently, my brother called me for a rather usual issue: his daughter’s iPhone’s storage is full. It’s a 16GB device, and yes, this is quite low for today’s youngsters, active with loads of photos, videos and social networks.

First thing first: understand what is eating up space and what is the general config for the photos library.

Let’s go to Settings / General / Storage and see what the storage usage is. Note down that iCloud Photos is enabled (this will be useful later) and check the list of apps sorted by storage used to (most to least). The first app on top of the list is Instagram, with 5.8GB used. Quite a lot, for nothing more than cache.

Unfortunately there is no button to clear the cache, only option is to Delete the App (completely) and reinstall it. By deleting the app, all documents and data related to it will be removed from the iPhone. Before proceeding, let’s be sure we know the password of the account. This was not the case, so before anything else, we went to the web site on and clicked the “forgot password” button, in order to reset it with a strong one.

Now we’re ready to Delete the App, as scary as it sounds. A few minutes later, close to 6GB of space have been released on the iPhone. We can reinstall the app, login with the well known new password and recover all our settings from the accounts (who we follow, etc).

Repeat this process with any other social network app that tends to keep too much cache, and free even more space.

The photos

The problem with iCloud Photos is that all devices (the iPhone and the Mac) are in sync. That means that deleting a photo on one device, deletes it on all devices. The optimize space option does not seem to work too well, since the iPhone complains of low storage.

Since the iCloud Photos is enabled, it is not possible to download the photos to the Mac using the USB cable directly in the iPhone in order to make an offline copy of the photos. Before we make any change to the Photos settings, we want to make a safe copy of the photos on our hard drive and avoid any loss. Let’s head to the Photos app on the Mac, and make sure all the photos are there thanks to iCloud (remember, we noted down that iCloud Photos was enabled). If not, activate iCloud photos on the Mac and wait for the sync to complete and the pictures to appear in the Photos App. Or alternatively, use the USB cable to import all photos from the iPhone to the Mac.

Now we have the Photos on the Mac, but we want to make an extra copy (to be on the safe side). In Photos let’s select all photos and click on File/Export. Make sure we opt for full size resolution and select a folder where to drop the photos. Click Export and let the Mac finish exporting all pictures to that folder (in our case we used a new folder in Downloads/Copy of iCloud Photos/. Once terminated, we have our safe copy, just in case.

Now back on the iPhone, let’s go to Settings / your name/ iCloud / Photos and deselect iCloud Photos. We get an option to remove all pictures from the phone or download them to the phone. Since we don’t have enough free storage, we opt for the delete option. After all, we have our backup on the local drive… We get a warning that the photos will be removed from the phone, but not from the iCloud library. That’s great, and it all makes sense since we have still our Mac using iCloud Photos. This setting, to use iCloud Photos or not, is device specific after all.

Our iPhone is clean now, with plenty of storage recovered. Our photos are still available on Photos on the Mac from iCloud. And from now on, we can plug our iPhone to the Mac on USB and import new photos to the Photos app on the Mac before deleting them from the phone.

How to boost your old Mac’s performance?

Your 6 year old Mac has become slow. The successive OS upgrades have somewhat killed the performance of your Mac. It takes several minutes to start-up, firing Photos is a nightmare and even Word requires 30+ sec to open.

It’s time to rejuvenate your Mac thanks to a new SSD disk.

I have installed a (secondary) SSD in several Mac:

– iMac 27″ mid 2011: SSD Sata III SanDisk Ultra II 960 GB (in addition to the internal orignal HDD )
– iMac 21″ mid 2011: SSD Sata III SanDisk Ultra II 480 GB (in addition to the internal orignal HDD )
– iMac 21″ mid 2015: SSD Crucial MX300  1 TB, mounted in external USB3 disk case (I didn’t dare opening the 2015 iMac, due to the glued glass).
– Mac Mini 2012: Crucial BX200 Flash SSD Internal 2,5″ 480GB SATA III (in addition to the internal orignal HDD )

On all these Mac the new SSD is the boot disk, and everything works perfectly.

The performance gain is spectacular. The iMac 27″ (core i5) starts in 20 sec (cold boot). The iMac 21″ 2011 boots in 1 min 20 sec instead of 3 min on the original HDD. Word opens in 2sec, Photos in 5 sec.

For a very decent price (200 to 350EUR), the Mac is as fast as a brand new one. The disk swap opeartion is a bit hard and I would not recommend to do it without a level of technical background. But the result is really worth the sweat.

Use your iMac as external screen for your Macbook

Just plug the Macbook to the iMac Thunderbolt port using a Thunderbolt-to-Thunderbolt cable. On the iMac, press Cmd-F2 and it switch to Screen only mode. No need to reboot the iMac.

On the Macbook, the monitor settings will allow to use the iMac as only external screen or as an extension of the Macbook screen as well as in duplicate mode (both screens showing the same).

Enjoy your Mac.

Comment utiliser un iMac comme écran externe d’un Macbook


Il suffit  de connecter le Macbook Air par un câble Thunderbolt-Thunderbolt au port Thunderbolt de l’iMac. Sur l’iMac, taper sur Cmd + F2 et il passe en mode écran.

Sur le portable, les réglages de moniteur, permettent d’utiliser l’écran comme extension (deuxième écran) ou en “copie vidéo”, c-à-d que les deux écrans affichent la même chose en parallèle.

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