Deep Scan vs Quick Scan

Quick Scan reads the file system’s metadata structures and uses them to find recently deleted files. The technique works because deleted files aren’t immediately erased; the file system just marks the file’s clusters as available for reuse and removes the file’s entry from its active catalog. The deleted entry often persists in the catalog for some time, and Quick Scan recovers it before the OS overwrites the original location.¹

What Quick Scan reads in each file system

Different file systems store deleted file metadata differently, so Quick Scan’s mechanics vary by file system:

• NTFS (Windows). The Master File Table (MFT) stores records for every file. When a file is deleted, its MFT record is marked unused but the data persists. Quick Scan reads the MFT and identifies records flagged as deleted; each record contains the file’s original name, size, timestamps, and cluster locations.
• FAT32 and exFAT. The directory table holds file entries; deleted files have their first character replaced with 0xE5. Quick Scan finds these marked entries and reads the original file metadata from them.
• ext4 (Linux). The inode table stores file metadata. Linux unfortunately wipes the inode on deletion, which makes Quick Scan less effective; the journal sometimes preserves recent deletions briefly.
• APFS (macOS). The Object Map B-tree references files. APFS’s snapshot mechanism sometimes preserves deleted files until the next snapshot rotation.
• HFS+ (legacy macOS). The Catalog File B-tree contains file metadata; deleted entries persist until the catalog is reorganized.

What Quick Scan finds

Quick Scan returns files with their full metadata intact:

• Original file names (not generic f00000001.jpg-style names).
• Folder structure matching the original organization.
• Original timestamps for creation, modification, and access.
• File system attributes like read-only flags, hidden flags, and (on appropriate file systems) ownership and permissions.
• Fragmented files handled correctly because the file system metadata describes how each file’s clusters map across the disk.

When Quick Scan fails

Quick Scan returns nothing useful in scenarios where the file system metadata it reads is gone or unreadable:

• After a full format that wiped the file system structures.
• On RAW partitions where the file system is unrecognizable.
• After severe file system corruption from ransomware, malware, or hardware damage to metadata regions.
• On file systems the recovery tool doesn’t support (proprietary or older formats).
• When deletion was long ago and the OS has overwritten the deleted file’s metadata records.

Typical Quick Scan time

Quick Scan completes quickly because it reads only the file system’s metadata structures, which are small relative to the disk’s total size. Typical times: 30 seconds for a 256 GB SSD; 2-5 minutes for a 1 TB HDD; 5-15 minutes for a multi-terabyte drive. The scan time depends mostly on the size of the file system metadata, not the total drive capacity. Drives with millions of small files have larger metadata structures and take proportionally longer; drives with a few large files complete almost instantly.²

Deep Scan performs signature-based file carving across the entire disk. It ignores the file system entirely and reads raw bytes, looking for known file format signatures (the binary patterns at the start of JPEG, PDF, ZIP, and hundreds of other file types). When it finds a recognized signature, it extracts the file content from that position forward.³

The signature-matching algorithm

Every file format has a recognizable starting pattern. JPEGs begin with FF D8 FF; PDFs begin with %PDF; ZIPs begin with PK; PNGs begin with 89 50 4E 47. Deep Scan reads the disk in blocks and compares each block’s start to a database of known signatures. A match indicates that a file of that type starts at that location; the scanner reads forward through the disk until it finds the file’s end (either a footer signature, a size field in the file’s header, or the next recognizable file’s beginning), then extracts everything in between as a recovered file.

What Deep Scan finds

Deep Scan succeeds in scenarios where Quick Scan fails:

• After full format wiped the file system metadata. The file content sectors are still there for Deep Scan to find.
• On RAW partitions with unrecognizable file systems. Deep Scan doesn’t need to recognize the file system.
• After ransomware corruption of metadata structures. The file content remains.
• On older deletions where Quick Scan would have lost the metadata records but the file content sectors haven’t been overwritten yet.
• When the file system version is too old, too new, or proprietary for the recovery tool’s parser.

What Deep Scan loses

The trade-off is significant:

• File names are gone. Deep Scan generates names like f00000001.jpg, f00000002.pdf, sequentially numbered.
• Folder structure is gone. Recovered files are typically organized by file type (a jpg/ folder, a pdf/ folder, a zip/ folder).
• Original timestamps are lost unless they’re embedded inside the file format (EXIF in JPEGs, ID3 in MP3s).
• Fragmented files often come back corrupted because file carving generally assumes contiguous storage; when a file is fragmented, the scanner reads the first fragment correctly but continues into different file’s content.
• False positives appear: random data sometimes coincidentally matches signature patterns and gets extracted as broken files.

Typical Deep Scan time

Deep Scan must read every block of the disk to look for signatures, so its time is proportional to drive capacity:⁴

• 256 GB SSD: 30-60 minutes.
• 1 TB HDD: 2-4 hours.
• 2 TB HDD: 4-8 hours.
• 4 TB HDD: 6-12 hours.
• 8 TB+ HDD: 12-24+ hours.
• Drives with bad sectors: dramatically slower, often 2-10x longer because each failed read takes seconds before timing out.
• USB 2.0 connections: 5-10x slower than internal SATA or USB 3.0.

The complete comparison in one table.⁵

Aspect	Quick Scan	Deep Scan
Underlying technique	File system metadata reading	Signature-based file carving
What it reads	NTFS MFT, FAT directory, ext4 inodes, etc.	Raw disk bytes, sector by sector
Typical scan time	30 seconds to 15 minutes	1-24+ hours
Scan time depends on	File system metadata size	Total drive capacity
Recovers file names	Yes	No (generic names)
Recovers folder structure	Yes	No (organized by file type)
Recovers timestamps	Yes	Only if embedded in file
Handles fragmented files	Yes	Limited
False positives	Rare	Common
Works on formatted drives	Limited	Yes
Works on RAW partitions	No	Yes
Works without file system support	No	Yes
Recovers older deletions	Limited	Yes (if not overwritten)
File types limited by	What the file system catalogs	Tool’s signature database
Output organization	Mirrors original folders	Flat by file type

Side-by-side strengths and weaknesses

The two techniques are universal across recovery software, but each vendor uses their own marketing terminology. The underlying mechanics are identical.⁶

Tool	Quick Scan name	Deep Scan name
Recuva	Quick Scan	Deep Scan
EaseUS Data Recovery Wizard	Quick Scan	Deep Scan (auto after Quick)
Disk Drill	Quick Scan	Deep Scan
Wondershare Recoverit	Quick Scan	Deep Scan
R-Studio	Standard scan	Extra Search for Known File Types
Stellar Data Recovery	Standard Recovery	Deep Scan
MiniTool Power Data Recovery	Quick Scan	Full Scan / Deep Scan
Tenorshare 4DDiG	Quick Scan	Deep Scan
iBoysoft Data Recovery	Standard Mode	Deep Scan / Bitmap Scan
iCare Data Recovery	Deleted File Recovery	Deep Scan Recovery / RAW Recovery
PhotoRec (free)	(no Quick mode)	(file carving only, Deep Scan equivalent)
TestDisk (free)	Quick Search	Deeper Search

Why the naming varies

The proliferation of names exists for marketing reasons rather than technical ones:

• Differentiation in product comparisons. If every tool used “Quick Scan” and “Deep Scan,” features wouldn’t appear distinctive in side-by-side comparisons.
• Avoidance of generic terminology. Some vendors prefer “Standard” and “Comprehensive” as more professional-sounding alternatives.
• Trademark and branding considerations. “Smart Scan” and “Bitmap Scan” are vendor-specific brand names rather than industry-standard terminology.
• Technical accuracy. “RAW Recovery” (EaseUS terminology) is technically accurate for the Deep Scan equivalent because file carving operates on raw disk content.

For users, the practical implication: look for two scan modes in any recovery tool, regardless of what they’re named. The fast one is Quick Scan equivalent; the slow one is Deep Scan equivalent. The decision logic is the same regardless of the tool.

The decision is straightforward in most cases. Quick Scan first, Deep Scan as fallback. The exceptions are narrow.⁷

When Quick Scan is the right choice

• Recently deleted files (within hours or days) on a working drive. Quick Scan likely finds them with original names.
• Recycle Bin emptied on Windows or Trash emptied on Mac. The file system catalog still has the entries.
• Accidentally Shift+Deleted files on Windows. Same as above, no Recycle Bin involvement but metadata still present.
• Time-sensitive recovery. Quick Scan finishes in minutes; Deep Scan takes hours. When you need files immediately, Quick Scan first.
• You need original file names and folder structure. Only Quick Scan preserves these.
• The drive is healthy and mounts normally. File system metadata is intact and readable.

When Deep Scan is the right choice

• Quick Scan returned nothing useful or only a few files when you expected more.
• The drive was reformatted. Full format wiped the file system metadata; only Deep Scan can find the file content.
• The drive shows up as RAW in Disk Management or Disk Utility. The file system is unrecognizable.
• Severe file system corruption after a crash, power loss, or malware. Quick Scan can’t read damaged metadata.
• Older deletions where the file system has overwritten the deleted entries. Deep Scan finds the file content if the data clusters haven’t been reused.
• File system not supported by the tool. If the tool can’t parse the file system, Deep Scan is the only option.
• You don’t need original organization. When you just want the photos back, generic file names are acceptable.

When to skip Quick Scan and go straight to Deep

Almost never, but the narrow scenarios where you might:

• You’ve already tried Quick Scan and it returned nothing useful. Don’t waste time running it again.
• The drive shows as RAW with no file system. Quick Scan has nothing to read; skip directly to Deep Scan.
• You’ve already done a full format. The file system is gone; Quick Scan will find nothing.

The auto-fallback pattern

Modern recovery software handles this decision automatically. EaseUS, Disk Drill, and Wondershare Recoverit all start with Quick Scan when you click “Scan,” then continue automatically to Deep Scan when Quick Scan finishes, showing combined results. This means you usually don’t need to choose between modes; just click Scan and let the tool run both. Some tools let you stop after Quick Scan if you’ve already found what you need; others always run both unless interrupted.