Scanning FAQs

Disk Drill has several different scanning methods that allow it to examine your storage device and locate lost files. Below you’ll find frequently asked questions about these methods. If you’re ready to get started with a scan, see How to Recover Lost Files with Disk Drill Basic. If you’ve completed a scan but don’t see the files you need, try Troubleshooting Scan Results.

Why is Disk Drill Asking to Make Changes to My Computer?

Like many programs, Disk Drill requires administrator password in order to work. It requires full access in order to be able to scan every bit of data on your drive. You will only need to give permission once after an installation or upgrade.

What Does Search for Lost Data Actually Do?

It chains multiple scanners automatically so you don’t have to guess the right order. Disk Drill first follows file‑system metadata (names/paths), then falls back to deep, signature‑based analysis for content‑only recovery. You can preview and even start recovering while the scan continues.

What Are the Chances My File Can Be Recovered?

File recovery is always uncertain (the one exception to this being Guaranteed Recovery). There are many factors that affect your chances. See our article on Variables That Impact Recovery Chances for a detailed explanation. If you are attempting to recover files from a Mac internal hard drive, be sure to follow our tutorial How to Recover Lost Files from Your Mac Internal Hard Drive, as there are extra precautions involved.

Why Isn't the Drive I Need to Scan Showing Up?

There are several reasons a drive might not show up in Disk Drill. In general, to scan an external device, you must be able to mount the device on your Mac or Windows (it should show up on the left-hand sidebar of your Finder/Explorer window) or see the volume using Disk Utility/Disk Management.

1. Drive connected after launching Disk Drill: Disk Drill actively monitors device connections, but if you plugged in the drive after the app was already open and it doesn’t show up, try the following steps. Quit Disk Drill, safely disconnect the device, then reconnect it. Verify the drive appears in Disk Utility (macOS) or Disk Management (Windows), and relaunch Disk Drill.
2. Hidden drives: Disk Drill automatically filters small‑capacity devices, system volumes, and partitions. To view them, click “Show hidden items” at the bottom‑right of the main window.
3. Failed controller/firmware (drive electronics): If a drive’s PCB or firmware is failing, it may not enumerate correctly—common symptoms include “Unknown/Not Initialized”, 0 bytes capacity, missing or garbled model/serial, repeated spin‑up/spin‑down, clicking/beeping, or only the USB bridge appearing (not the disk itself). Disk Drill—and any software—requires the OS to expose block‑level access; if the device doesn’t identify properly, software scanning isn’t possible.
4. Mapped network drives: Unfortunately, most mapped network drives and drives on most network-attached devices (which are connected to your Mac via SMB, AFP, FTP, NFS, RFS  and other file protocols) are not available for recovery or protection in Disk Drill. These network protocols do not provide the direct disk access required by Disk Drill. However, in cases where there’s either a DMG (Disk Image) or a sparse bundle mounted from a mapped network drive, and your Mac OS can access that mounted drive as a separate disk, then Disk Drill will probably be able to scan the disk.
5. iPod disks: iPods must have “Manually manage music and videos” enabled in iTunes.
6. Physical disk damage: If a disk has physical damage, such as significant bad sectors, then it may not be visible in Disk Drill. Unfortunately, if you can’t mount the disk on your Mac or Windows, Disk Drill can’t see the disk or recover data from it. If your hard drive does not seem like physically damaged, make sure it’s extensively cooled and run the scan again, cleaning the list of Bad Blocks populated within Disk Drill (macOS only).
7. iOS devices: Unlock the iPhone/iPad, connect it by cable, and tap Trust This Computer, then enter the passcode. On Windows, make sure Apple Mobile Device Support/iTunes is installed so the driver loads. Once paired, the device will appear in Disk Drill for iOS (backup‑based) recovery.
8. Android device: For full, low‑level scanning of internal storage, the device must be rooted—Android does not expose raw file‑system access without root. (No root is required to scan a removable microSD card—use a card reader for best results).
9. SIP‑protected devices (macOS): If a Mac’s System Integrity Protection (SIP) blocks low‑level access (e.g., startup/system volumes), install and approve Disk Drill’s system extension (kext) when prompted. You may need to approve it in System Settings → Privacy & Security and restart. After approval, rescan.
10. NAS devices: Make sure your NAS supports SSH and that SSH is enabled in its settings. In Disk Drill, choose NAS & Linux via SSH, enter the NAS’s IP/port (default 22) and credentials (an administrator/root‑level account is recommended), then select the underlying Linux volume/array to scan.
11. RAID arrays: Make sure all member disks are connected to your Mac/PC at the same time and recognized by the OS. If you’re using a hardware RAID controller/enclosure, connect through the original controller so the array is exposed as a single logical disk. For software RAID (AppleRAID, mdadm, Windows Dynamic/Storage Spaces), let the OS assemble the array first, then rescan in Disk Drill. If Disk Drill can’t virtually reconstruct your RAID—or if any member drive shows signs of failure—stop all writes and contact the CleverFiles Professional Data Recovery Lab.

Why Isn't the Partition I Need to Scan Showing Up?

Lost partitions are a fairly common occurrence, but the good news is Disk Drill can help. If a partition you expect to see is missing, a disk error or formatting issue has likely occurred. In these cases, use Lost Partition Search: if enough metadata remains, Disk Drill can surface the missing volume with its original file system and folder structure, letting you browse and recover files as they were.

In addition, Disk Drill may have detected bad sectors on the drive. Check to see if there are bad sectors listed by selecting the volume in question and clicking on Specify Bad Blocks (macOS only) in context menu. If there are any listed, highlight them and click “Delete” to remove them. Then run the scan again to see if it helps. If bad sectors are reported again, it means the disk has physical issues that are causing malfunctioning.

In either case, the best solution is to Backup Into DMG Image and make a complete copy of the disk (saving it to a separate hard drive of course) before things get worse. Once you have the new DMG Image, select it and click the universal Search for lost data button so that it will run through all of Disk Drill’s lost partition protocols.

What Does Each Scanning Option Do?

Clicking the universal Search for lost data button will go through all of the available scanning options, based on their availability for that disk. But you can also right‑click the disk to open the context menu and select an individual scanning method. The available methods vary depending on the type of disk/partition selected:

• Quick Scan: The Quick Scan option allows you to recover files with all of their metadata intact – including file names. It is a good option if you have just deleted the file you are trying to recover. If has been a while since the file was lost, then you will probably need to use Deep Scan. As its name implies, Quick Scan is quicker than Deep Scan, but may not find as many files.
• Deep Scan: A Deep Scan takes the longest, but it is the most thorough and can find files that the other scanning methods can’t. Deep Scan works on any file system – and even drives or partitions without a file system. It can also rebuild the original file system and folder structure on lost, formatted, or damaged volumes when sufficient metadata remains. When that metadata is unavailable, Deep Scan will still recover files by signature, but names and folder paths may be generic.
  ➡️ See this article for a longer explanation of how Deep Scan works.
• Advanced Camera Recovery (ACR): ACR targets one of the toughest real‑world problems—severely fragmented camera video. It runs a five‑stage pipeline (identify fragments → confirm camera/cluster → base files → low‑res proxies → final high‑res video) and supports many camera ecosystems (GoPro/DJI/Canon/Sony, etc.). Always scan the original card (or its byte‑to‑byte image) via a card reader for the best results.
• Local TM Snapshots: Scans Time Machine’s local APFS snapshots on your Mac’s internal system volume, exposing point‑in‑time copies of data for recovery.
• Allocate Existing File System Data: If the Finder/Explorer fails to read your data, Disk Drill uses its own method to scan the volume or partition and attempt to retrieve the existing data (files, folders, etc.).
• Universal Partition Search: This function allows you to recover partitions on FAT32, exFAT, NTFS, EXT (3 or 4), APFS, HFS+ volumes. It works on a disk level, and treats the disk as binary entity, quickly scanning the disk for signatures of known partition headers. Any found partition is displayed as a virtual item and can then be scanned for lost files.
• Scan for Lost HFS+ Partition: This method finds and rebuilds HFS+ partitions on your Mac that have been reformatted. It works on a partition level, and scans the partition for the backup copy of the HFS+ partition header. It then uses the backup copy to attempt to recover the data structures that existed before the partition was deleted (formatted). Any found partition is displayed as a virtual item and can then be scanned for lost files.
• Rebuild HFS+ Catalog File: The Rebuild function attempts to rebuild the catalog of HFS+ partitions that won’t mount correctly. Disk Drill uses the existing partition header to locate the B-tree catalog of the HFS+ partition and optimizes it by rebuilding its B-tree structure. The newly rebuilt directory is displayed as a virtual disk tree that you can browse and recover from. Since the release of Disk Drill 3, the HFS+ recovery has been enriched with new partition-related recovery algorithms.
• Undelete Protected Data: This is your best option if you installed Disk Drill before you suffered data loss, and you had the Recovery Vault and/or Guaranteed Recovery features enabled to protect the particular disk you need to retrieve deleted files from.
• Personal Data Scan: Parses Apple Contacts and Calendar data stores on the system volume and lists individual contacts and calendar events as separate nodes in the recovery results for targeted recovery.

How Can I Filter My Scan Results?

When a scan is finished, Disk Drill will show you a list of all the deleted files it was able to find. To make finding the deleted file you need easier, you can use the toolbar above the scan results to filter them:

• File Name: Type a keyword into the box with the magnifying glass on the upper left. This will search keywords in filenames but NOT file contents. A keyword search will not work with files recovered by Deep Scan (based on signatures), since filenames are not preserved. Deep Scan files are assigned a generic file name such as “file123.doc,” or, if there is some meta-info available, they might be named according to some of their file properties, such as a photo being named by its dimensions like “1920×680.jpg.”
• Date: Click the drop-down menu “Data modified” to restrict the list to files deleted within a specific time frame.
• File Type: Click one of the file types in the toolbar to restrict the list to one type of files. File type choices are: Pictures, Video, Audio, Documents, and Archives.
• File Size: Select “Large than” or “Less than ” from the drop-down menu, then type a file size to limit the results to a particular file size.
• Column Header: Click on any of the column headers (Name, Kind, etc.) to sort the list by that value. Click the heading twice to reverse the sort order (i.e. click once to sort from A-Z and twice to sort from Z-A).
• Recovery Chances: Filter results by Disk Drill’s predicted likelihood of successful recovery so you can quickly prioritize files with better prospects.

Why Don't You Recommend Scanning a System Partition?

Short answer: The system (boot) drive is constantly being written to. Modern operating systems and apps generate a huge volume of background writes—logs, caches, indexers, antivirus, cloud sync, updates, swap/pagefile, crash dumps, etc. Those ongoing writes can quickly overwrite the very blocks where your deleted files used to live. On SSDs, TRIM/UNMAP accelerates this process by invalidating freed blocks, which can make recovery impossible within minutes or hours.

Best practice (to maximize recovery chances)

1. Power off the computer immediately. Avoid any further activity on the system drive.
2. Detach the system drive (if feasible) and connect it to another Mac/PC as a secondary device (USB/NVMe enclosure, SATA dock, or HBA).
3. In Disk Drill, create a Byte‑to‑Byte Backup (sector‑level image) of the drive.
4. Scan the image, not the original disk.
5. Recover to a different physical drive—never back to the source.

If removing the drive isn’t possible: Boot the machine from a different startup volume (external disk) so the system partition stays idle, then image and scan from there. Even when recovery software minimizes writes, the operating system does not—so reducing or eliminating writes to the affected volume is critical.

How do I Stop, Save or Load a Scanning Session?

During a scan, you have several options:

• Stop: To stop a scan, click the Stop button on the upper-right of the recovery window. Your scanning session will be saved automatically and you can continue it at a later time.
• Pause: During Deep Scans, the Stop button turns to a Pause button. Click the Pause button to halt a scan. The Pause button will then turn to a Resume button. Click Resume to continue the scan.
• Save or Export: When you click Stop or Pause, your scanning session will saved automatically inside the Disk Drill database. But if you wish to export the scan data, such as for transferring it to another installation of Disk Drill, you read detailed explanation in our guide.
• Resume: If Disk Drill has a saved scan for that disk or partition, you’ll see a gray info banner beneath the Search for lost data button that reads “Load last scan (X days ago)”. Click it to reopen the previous scanning session.
• Load or Import: To load scan data saved elsewhere, simply double‑click the Session file from its saved location; Disk Drill will open the session and display the results.

How Long Should a Scan Take?

Recovery can take days! If you have a large drive that you are Deep Scanning, be prepared to wait. A 500 GB drive can take around 6 hours, 1 TB drive can take around 30 hours to scan — but every situation is different, so this is just a rough estimate! Be sure that you have shut down all applications (such as Time Machine, iPhoto, iTunes) that might be accessing the disk before you start the scan.

At the beginning of the scan process, you may see thousands of hours estimated. Just let it continue scanning. The estimate will usually drop to a more manageable number over time. If it doesn’t, or it seems stuck, please contact support. Keep in mind it is from 2025 and speed has been increased with Disk Drill 6.

Recovering the scan results to an external drive, or backing up a drive as a DMG image, can take a long time too. Be aware that the type of external drive and the type of port used to connect it to your Mac or PC will affect recovery time. Use the fastest port you have available. Try a different port or USB cable if things seem excessively slow.

If you are done your scan and don’t see the files you need, try Troubleshooting Scan Results.

Trying to Scan an APFS Volume With 8kb Blocks, Which Appeared After a Large-size Drive Was Formatted From HFS to APFS on macOS?

Typically a standard block size on APFS volumes is 4KB. Such a structure is fully supported by Disk Drill’s various scanning methods, however it is possible that at some point your APFS volume was created by formatting an HFS one on macOS, then you may have ended up with some non-standard 8KB blocks on your volume. As extremely rarely as it happens it still does, and at this point unfortunately 8KB blocks on such APFS volumes are not supported by Disk Drill’s scanning methods.