{"id":4822,"date":"2026-04-01T10:17:07","date_gmt":"2026-04-01T08:17:07","guid":{"rendered":"https:\/\/reparationmac.be\/?p=4822"},"modified":"2026-04-04T05:37:59","modified_gmt":"2026-04-04T03:37:59","slug":"mac-disk-utility-guide","status":"publish","type":"post","link":"https:\/\/reparationmac.be\/en\/utilitaire-disque-mac-guide\/","title":{"rendered":"Disk utility: the complete guide"},"content":{"rendered":"<div class=\"article-blog\">\n\n<h1>Mac Disk Utility: a complete guide to managing your disks<\/h1>\n\n<div class=\"article-meta\">Reading: 11 min | macOS Tutorials<\/div>\n\n<img fetchpriority=\"high\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/04\/utilitaire-disque-mac-guide-complet.webp\" alt=\"Mac Disk Utility guide manage APFS disks\" title=\"Mac Disk Utility: a complete guide to managing your disks\" width=\"1200\" height=\"568\" loading=\"eager\">\n\n<div class=\"answer-box\">\n<strong>In a nutshell:<\/strong> Disk Utility is macOS's built-in tool for managing your disks and volumes. It lets you check and repair a disk, format a USB key or external disk, partition a disk, erase a Mac before resale, mount and unmount volumes and create disk images. It's an essential tool for troubleshooting and maintaining your Mac.\n<\/div>\n\n<div class=\"toc-box\">\n<strong>Contents<\/strong>\n<ul>\n<li><a href=\"#ouvrir\">How to open the Disk Utility<\/a><\/li>\n<li><a href=\"#interface\">Understanding the interface<\/a><\/li>\n<li><a href=\"#verifier-reparer\">Checking and repairing a disc<\/a><\/li>\n<li><a href=\"#formater\">Formatting a disk or USB key<\/a><\/li>\n<li><a href=\"#formats-disque\">APFS, HFS+, exFAT: which format to choose<\/a><\/li>\n<li><a href=\"#partitionner\">Partitioning a disk<\/a><\/li>\n<li><a href=\"#effacer-mac\">Deleting a Mac before resale<\/a><\/li>\n<li><a href=\"#image-disque\">Create a disk image<\/a><\/li>\n<li><a href=\"#faq\">Frequently asked questions<\/a><\/li>\n<\/ul>\n<\/div>\n\n<h2 id=\"ouvrir\">How to open the Disk Utility<\/h2>\n\n<p>From macOS: open the Finder, go to Applications, Utilities, then Disk Utility. You can also find it via Spotlight (<strong>Cmd + Space<\/strong> and type \u00abDisk Utility\u00bb).<\/p>\n\n<p>From recovery mode (when macOS won't boot): boot into recovery mode (power button held down on Apple Silicon, Cmd + R on Intel) and select Disk Utility from the menu. This is the method to use when you need to repair the boot disk or prepare a disk for a clean installation of macOS.<\/p>\n\n<h2 id=\"interface\">Understanding the interface<\/h2>\n\n<p>The Disk Utility displays two levels in the sidebar: physical devices (disks) and logical volumes (partitions). To see both, click on <strong>Presentation<\/strong>, then <strong>Show all devices<\/strong>. This option is important because some operations (such as full formatting) are only available at physical device level.<\/p>\n\n<table class=\"tg-table\">\n<thead>\n<tr>\n<th>Element<\/th>\n<th>What it is<\/th>\n<th>When to select it<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><span class=\"cell-label\">Physical device<\/span><\/td>\n<td><span class=\"cell-desc\">The hard disk or SSD (e.g. \u00abAPPLE SSD AP0512Q\u00bb)<\/span><\/td>\n<td>To format completely, change the partition scheme<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">APFS container<\/span><\/td>\n<td><span class=\"cell-desc\">The APFS logical container, which groups volumes<\/span><\/td>\n<td>To see the space shared between volumes<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">Volume<\/span><\/td>\n<td><span class=\"cell-desc\">The accessible partition (e.g. \u00abMacintosh HD\u00bb)<\/span><\/td>\n<td>To check, repair or delete a volume<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n<img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/04\/interface-utilitaire-disque-mac-volumes.webp\" alt=\"Mac Disk Utility Interface APFS HFS volumes\" title=\"macOS Disk Utility interface with volumes and devices\" width=\"1200\" height=\"568\" loading=\"lazy\">\n\n<h2 id=\"verifier-reparer\">Checking and repairing a disc<\/h2>\n\n<p>The \u00abS.O.S.\u00bb (or \u00abFirst Aid\u00bb) function checks the integrity of the file system and repairs any errors detected. (or \"First Aid\") function checks the integrity of the file system and repairs any errors it detects. This is the first response when your Mac behaves strangely: corrupted files, unexplained slowness, start-up errors.<\/p>\n\n<p>Select the volume to be checked in the sidebar, then click on <strong>S.O.S.<\/strong> at the top of the window. Click on \u00abRun\u00bb. The utility analyses the disk structure and corrects any errors found.<\/p>\n\n<div class=\"info-box warning\">\n<strong>Please note:<\/strong> You cannot repair the boot disk while macOS is using it. To repair \u00abMacintosh HD\u00bb, boot into recovery mode and launch Disk Utility from there. See the <a href=\"https:\/\/support.apple.com\/fr-be\/guide\/disk-utility\/welcome\/mac\" rel=\"noopener\" target=\"_blank\">Apple documentation on disk repair<\/a> for full details.\n<\/div>\n\n<h2 id=\"formater\">Formatting a disk or USB key<\/h2>\n\n<p>Formatting erases all the data on a disk and prepares it for a specific use. Select the physical device (not the volume) in the sidebar, click on <strong>Delete<\/strong>, Choose a name, format and layout, then confirm.<\/p>\n\n<div class=\"info-box danger\">\n<strong>Irreversible :<\/strong> Formatting permanently deletes all the data on the disk. Triple-check that you have selected the correct drive before clicking \u00abErase\u00bb. Make a backup of everything you want to keep.\n<\/div>\n\n<h2 id=\"formats-disque\">APFS, HFS+, exFAT: which format to choose<\/h2>\n\n<table class=\"tg-table\">\n<thead>\n<tr>\n<th>Format<\/th>\n<th>Recommended use<\/th>\n<th>Mac compatible<\/th>\n<th>Windows compatible<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><span class=\"cell-label\">APFS<\/span><\/td>\n<td><span class=\"cell-desc\">Mac internal SSD, Mac external drive only<\/span><\/td>\n<td>macOS High Sierra (10.13) and above<\/td>\n<td>No (read-only with third-party tools)<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">Encrypted APFS<\/span><\/td>\n<td><span class=\"cell-desc\">Mac internal SSD with FileVault, sensitive disks<\/span><\/td>\n<td>macOS High Sierra and above<\/td>\n<td>No<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">Mac OS extended (HFS+)<\/span><\/td>\n<td><span class=\"cell-desc\">Mechanical hard drives, Time Machine on HDD<\/span><\/td>\n<td>All versions<\/td>\n<td>No (read-only with third-party tools)<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">exFAT<\/span><\/td>\n<td><span class=\"cell-desc\">USB keys and Mac\/Windows shared drives<\/span><\/td>\n<td>Yes<\/td>\n<td>Yes<\/td>\n<\/tr>\n<tr>\n<td><span class=\"cell-label\">MS-DOS (FAT32)<\/span><\/td>\n<td><span class=\"cell-desc\">USB keys for older devices, files under 4 GB<\/span><\/td>\n<td>Yes<\/td>\n<td>Yes<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n<p><strong>In a nutshell:<\/strong> APFS for everything Mac only (SSDs), HFS+ for Time Machine mechanical hard drives, exFAT for drives shared between Mac and PC.<\/p>\n\n<h2 id=\"partitionner\">Partitioning a disk<\/h2>\n\n<p>Partitioning divides a disk into several independent volumes. With APFS, macOS favours APFS volumes rather than traditional partitions: the volumes share the free space of the container dynamically, which is more flexible.<\/p>\n\n<p>To add an APFS volume: select the APFS container in the sidebar, then click the \u00ab+\u00bb button above the list of volumes. Give the volume a name and choose the APFS format. The space is shared automatically.<\/p>\n\n<p>To create a classic partition (required for Windows dual-boot): select the physical device, click on <strong>Partition<\/strong>, Add a partition with the desired format (exFAT for Windows) and adjust the size.<\/p>\n\n<h2 id=\"effacer-mac\">Deleting a Mac before resale<\/h2>\n\n<p>Before you sell or give away your Mac, you need to erase all your data and reinstall macOS. Here's how:<\/p>\n\n<p><strong>1.<\/strong> Back up your data (Time Machine). <strong>2.<\/strong> Sign out of iCloud (System settings, your name, Sign out). <strong>3.<\/strong> Start up in recovery mode. <strong>4.<\/strong> Open Disk Utility. <strong>5.<\/strong> Select \u00abMacintosh HD\u00bb and click on Delete (APFS format). <strong>6.<\/strong> Exit the Utility and install macOS from recovery mode.<\/p>\n\n<p>For a complete guide with all the checks, see our <a href=\"\/en\/reset-mac-to-factory-settings\/\">Mac reset tutorial<\/a>. If you want to sell your Mac, find out more about our <a href=\"\/en\/mac-buyback-belgium\/\">Mac buyback service in Belgium<\/a>.<\/p>\n\n<img decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/04\/effacer-mac-utilitaire-disque-revente.webp\" alt=\"Erase Mac Disk Utility before reselling APFS\" title=\"Erasing a Mac with Disk Utility before resale\" width=\"1200\" height=\"568\" loading=\"lazy\">\n\n<h2 id=\"image-disque\">Create a disk image<\/h2>\n\n<p>Disk Utility can create disk images (.dmg), files that behave like virtual disks. This is useful for archiving a folder as a single image, creating an encrypted volume to store sensitive files, or distributing a set of files as a single downloadable file.<\/p>\n\n<p>Go to File, New image, then choose \u00abImage from folder\u00bb to archive an existing folder, or \u00abEmpty image\u00bb to create an empty container. You can encrypt the image with AES-128 or AES-256 to password-protect its contents.<\/p>\n\n<h2 id=\"faq\">Frequently asked questions<\/h2>\n\n<div class=\"faq-section\">\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>S.O.S. has found errors but can't fix them. What can you do?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>Restart in recovery mode and relaunch S.O.S. from there. If the errors persist, back up your data, erase the disk and reinstall macOS. If the disk shows hardware errors, it may be at the end of its life and needs to be replaced.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>What is the difference between APFS and HFS+?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>APFS (Apple File System) is the modern format optimised for SSDs: faster, better space management, native encryption, snapshots. HFS+ (Mac OS extended) is the old format, still used for mechanical hard drives and Time Machine on HDDs. For SSDs, always use APFS.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>How do I format a USB flash drive so that it works on both Mac and PC?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>Format it in exFAT with a GUID partition scheme (or MBR for drives smaller than 32 GB). exFAT is the only modern format that works natively for reading and writing on Mac and Windows, with no file size limit.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>Can I partition my internal SSD to install Windows?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>On Intel Macs, yes, via Boot Camp. On Apple Silicon Macs, Boot Camp is not available. You can use virtualisation solutions such as Parallels Desktop or UTM to run Windows on Apple Silicon Macs.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>Can the Disk Utility recover data?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>No, Disk Utility does not recover deleted data. It can repair a corrupt file system (making files accessible again), but it does not restore deleted files. For recovery, see our <a href=\"\/en\/restore-mac-trash\/\">file recovery guide<\/a>.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>My external drive doesn't appear in Disk Utility<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>Try another cable and another USB port. Click on Overview, Show all devices. If the drive still doesn't appear, it may be faulty. Test it on another computer to confirm. A drive that makes unusual clicks or noises is faulty.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>What does \u00abGUID partition table\u00bb mean?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>This is the standard partition scheme for modern Macs. GUID (Globally Unique Identifier Partition Table) is required to boot macOS and to use APFS. Always choose GUID except for USB sticks intended for very old devices (which require MBR).<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>Can formatting be undone?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>No, formatting is irreversible via Disk Utility. However, data recovery software can sometimes recover files after formatting, especially if the disk has not been rewritten since. Act quickly and do not store anything on the formatted disk.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>Can the Disk Utility repair an external disk?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>Yes, the S.O.S. function works on all disks connected to the Mac: internal, external, USB keys, SD cards. Select the volume of the external drive and launch S.O.S.<\/p><\/div>\n<\/div>\n\n<div class=\"faq-item\">\n<div class=\"faq-question\"><span>How do I convert a disk from HFS+ to APFS?<\/span><span class=\"faq-toggle\">+<\/span><\/div>\n<div class=\"faq-answer\"><p>Select the HFS+ volume in Disk Utility, then go to Edit, Convert to APFS. The conversion preserves your data. However, this conversion is only possible in the direction HFS+ to APFS, not vice versa. As a precaution, back up first.<\/p><\/div>\n<\/div>\n\n<\/div>\n\n<div class=\"related-links\">\n<strong>Related articles<\/strong>\n<ul>\n<li><a href=\"\/en\/create-bootable-macos-usb-drive\/\">Create a bootable macOS USB key<\/a><\/li>\n<li><a href=\"\/en\/reset-mac-to-factory-settings\/\">Reset Mac to factory settings<\/a><\/li>\n<li><a href=\"\/en\/time-machine-mac-backup\/\">Time Machine: configuring Mac backup<\/a><\/li>\n<li><a href=\"\/en\/start-mac-in-safe-mode\/\">Starting a Mac in Safe Mode<\/a><\/li>\n<\/ul>\n<\/div>\n\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Utilitaire de disque Mac : guide complet pour g\u00e9rer vos disques Lecture : 11 min | Tutoriels macOS En r\u00e9sum\u00e9 : L&rsquo;Utilitaire de disque est l&rsquo;outil int\u00e9gr\u00e9 \u00e0 macOS pour g\u00e9rer vos disques et volumes. Il permet de v\u00e9rifier et r\u00e9parer un disque, formater une cl\u00e9 USB ou un disque externe, partitionner un disque, effacer [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":4827,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_breakdance_hide_in_design_set":false,"_breakdance_tags":"","footnotes":""},"categories":[13],"tags":[91,123,154,157,147,156,53,159,158,155,134,119],"class_list":["post-4822","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tutoriels-macos","tag-apfs","tag-cle-usb","tag-exfat","tag-formatage","tag-hfs","tag-image-disque","tag-macos","tag-partition","tag-reparation-disque","tag-sos","tag-ssd","tag-utilitaire-de-disque"],"_links":{"self":[{"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/posts\/4822","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/comments?post=4822"}],"version-history":[{"count":0,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/posts\/4822\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/media\/4827"}],"wp:attachment":[{"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/media?parent=4822"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/categories?post=4822"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/reparationmac.be\/en\/wp-json\/wp\/v2\/tags?post=4822"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}