Even with all of Disk Drill’s advanced algorithms, there are still some things that lessen your chances of a successful file recovery. One of those things is large file size — files like high resolution videos, presentations, graphic files, etc. Why is it that the large files are harder to recover? The answer is disk fragmentation.
Basically, when you first start using a hard drive, the free space is in one nice large chunk. But as you save files and then delete them over time, the chunks of free space get separated, or fragmented. Imagine if your hard drive got completely full, and then you deleted eight 100MB files. This would leave you with 800MB of free space, but it would be spread out over 8 different locations on your drive. If you try to save a 200MB file, your computer will split the file in half and store it in two of those slots. Your computer then “remembers” where those pieces are and collects them as needed.
So, when you use Disk Drill to recover files on your hard drive, the large files are almost always in bits and pieces. In some cases, Disk Drill can locate the “index” for the file system that will tell it where to find each piece, but in other cases, that index is lost and the pieces become unrecoverable.
TL;DR
- Big files are typically split across many non‑contiguous chunks (“extents”). When metadata is lost, reassembling those chunks is tough—especially on SSDs.
- SSDs often purge deleted data via TRIM, making post‑deletion recovery of large files unlikely once garbage collection runs.
- Modern filesystems (NTFS, ext4, APFS) optimize for speed and reliability, not forensic recovery. Features like copy‑on‑write, delayed allocation, sparse files, and encryption complicate reconstruction.
- Disk Drill mitigates risk with byte‑to‑byte backups, Deep Scan signature carving, partition discovery, Recovery Vault, Guaranteed Recovery and (new in v6) Advanced Camera Recovery that can rebuild fragmented videos from cameras and drones.
The Core Problem: Big Files are Rarely Stored in One Piece
On disk, large files don’t live in a single, neat block. Filesystems allocate space in runs/extents spread across the volume. In NTFS, the file’s $DATA is typically non‑resident, and its location is tracked by a run list; if a file is fragmented enough, NTFS uses $ATTRIBUTE_LIST to spill this metadata over multiple MFT records. Lose or damage that mapping, and the data is still there—but you no longer know which pieces belong together.
Linux’s ext4 writes big files as extents and uses delayed allocation to boost performance; that can change where data ultimately lands and, after crashes, complicate what remains on disk.
On Apple devices, APFS relies heavily on copy‑on‑write (CoW) metadata, snapshots, clones, and strong encryption—excellent for reliability and space efficiency, but they introduce layers of indirection that make reconstruction harder when directory metadata is gone.
Why Large Files Fail Recovery More Often
🧩 Fragmentation Multiplies The Ways Recovery Can Go Wrong
The bigger the file, the more extents it tends to have. If metadata is intact, recovery software can read those extents in order. If metadata is damaged or overwritten, tools fall back to file carving (looking for file signatures). Carving handles contiguous files well, but struggles to reassemble fragmented files without extra format knowledge—typical for very large videos, disk images, and VM containers. This limitation is well‑documented in digital forensics literature.
✂️ SSDs + TRIM Often Erase Your “Second Chance”
When you delete a file on an SSD, the OS can send TRIM to mark those blocks as unused. The drive’s garbage collection is then free to erase them in the background. Once that happens, raw data is gone—carving won’t help. Depending on firmware and timing, recovery after TRIM is frequently impossible.
🔏 Encryption Raises The Stakes
Full‑disk encryption (BitLocker, FileVault/APFS) protects you—but it also means that minor metadata loss can render large, fragmented content unrecoverable without the keys. APFS uses strong encryption; Windows BitLocker encrypts entire volumes.
🌟 Modern Conveniences That Complicate Recovery
- Copy‑on‑write clones & snapshots (APFS): the same logical file may reference blocks scattered across versions. Lose the mapping, and reassembly becomes much harder.
- Sparse files (NTFS): big files like VHDX/DBs can have large “holes” that were never allocated; carving can’t magically recreate holes or their original layout.
Why Carving Often Fails For Large Files
Signature scanning (a.k.a. Deep Scan) looks for headers/footers (e.g., MP4/MOV boxes). It works best when the file is contiguous. With multi‑gigabyte videos or disk images that are split across dozens or hundreds of extents, a carver must guess join points—typically a non‑starter without format‑aware heuristics. Research and tool testcases repeatedly show lower accuracy on fragmented targets.
How Disk Drill Helps When The File is Huge
1) Protect The Evidence With a Byte‑To‑Byte Backup
Before heavy scanning, create a read‑only, sector‑for‑sector image of the problem device. Disk Drill’s Byte‑to‑Byte Backup does exactly that, so you scan the image, not the failing disk—minimizing wear and avoiding further overwrites.
2) Use The Right Scan For The Situation
- 📝 Deep Scan (signature carving): When metadata is gone, Disk Drill scans byte‑by‑byte for known file signatures. For huge media, containers, and archives, it can often rebuild playable files even without directory entries (names may be generic).
- 🗂️ Deep Scan (file system carving): Disk Drill can locate lost partitions and use metadata to restore original folder/filenames—ideal for large files when mapping still exists.
- 📸 Advanced Camera Recovery for fragmented video: New in Disk Drill 6, Advanced Camera Recovery (ACR) targets one of the hardest cases – fragmented video from cameras/drones/action cams. ACR uses format‑aware reconstruction to piece together scattered video streams into playable files—even after formatting the card. This is designed for footage from devices like GoPro, DJI, Canon, Sony, Insta360, and more.
What Leads to Fragmentation of Large Files?
- Append‑heavy workflows. Logging, NLE/video editing, VM disks, databases, and containers (VHD/VHDX) grow over time, often forcing the filesystem to append new extents elsewhere. Microsoft warns that dynamically expanding virtual disks can become highly fragmented as they expand.
- Low free space & churn. As free space splinters into small gaps, large files rarely fit contiguously. This is classic fragmentation behavior observed across filesystems.
- Many large assets written concurrently. Downloading, camera offloads, and renders may interleave blocks from multiple big files. (General fragmentation causes documented by platform vendors and references.)
HDD (CMR) vs SSD vs HDD (SMR): Your Medium Matters
HDD (CMR “Conventional”) Drives
On classic hard drives, tracks don’t overlap and random writes don’t force large read‑modify‑write cycles. When you delete a file, the data typically remains on the platter until it’s overwritten, so sector‑by‑sector imaging and signature carving often work—especially if the large file was relatively contiguous. CMR HDDs generally don’t implement TRIM, so there’s no controller‑initiated purge of “discarded” sectors after deletion.
SSD Drives
Solid‑state drives remap LBAs through a flash translation layer (FTL). After a delete, the OS can issue TRIM/UNMAP so the controller knows which pages are invalid; garbage collection may then erase or recycle those pages. Once that happens, there’s nothing meaningful left at those logical locations—large‑file recovery becomes infeasible unless the blocks were never trimmed or erased.
HDD (SMR) Drives
Shingled Magnetic Recording boosts areal density by overlapping tracks like roof shingles. To keep writes safe, SMR groups tracks into zones (a.k.a. bands) that must be written sequentially; typical zone sizes are on the order of 256 MiB to 1 GiB. Unlike CMR HDDs, many SMR models implement ATA TRIM / SCSI UNMAP (sometimes surfaced in tools as “Optimize”). The command doesn’t flip bits like flash, but it tells the drive which LBAs no longer hold user data so the firmware can minimize background movement and reclaim space when rewriting zones. That can reduce the chance that “deleted” bands still contain intact remnants—especially on DM‑SMR where cleaning can rewrite large spans (support is model‑dependent).
What this means for large‑file recovery (practical takeaways):
| CMR HDDs | On CMR HDDs, your best shot is fast, read‑only imaging and metadata‑guided recovery; if metadata is gone, deep carving may still reassemble long contiguous runs. |
| SSDs | On SSDs, once TRIM+GC have invalidated/erased pages, recovery is typically not possible. Move immediately to imaging before the drive idles long enough to clean. |
| SMR HDDs | On SMR HDDs, behavior sits between CMR and SSD: data may linger, but background media‑cache cleaning and (where supported) TRIM/UNMAP can rewrite or invalidate whole regions later. Expect more indirection and less predictable physical locality than CMR—especially harmful for very large, fragmented files. Image the disk promptly, and avoid any workload that could trigger heavy rewriting within zones. |
Bottom Line
Large files are tough because they’re internally complex (many extents), stored on complex media (SSD+TRIM), and managed by complex filesystems (CoW, snapshots, encryption). The best strategy is to preserve the evidence (byte‑to‑byte image), then scan intelligently. Disk Drill brings the right tools—particularly for big media and camera footage—to give you the best possible shot.