Most people treat a USB stick as a disposable envelope: write the files, hand it over, forget it. The drive then sits in a drawer for two years, gets used to carry a 40 GB video folder, and dies halfway through the copy. Very little of that is bad luck. Almost every stick failure I have dealt with came down to one of four things — a fake capacity, a filesystem that could not take the file, the cable being pulled mid-write, or the absence of a second copy anywhere.
Test a new drive’s real capacity before you trust it
A counterfeit stick reports 1 TB in File Explorer while physically holding 8 GB or 16 GB of flash. The controller wraps around once you pass the real limit, so earlier files get overwritten while the window still lists them. You discover it weeks later, when a photo archive opens as grey thumbnails.
H2testw settles the question. It is free, Windows-only, and writes numbered files until the drive is full, then reads every one back. Empty the stick first, select the drive letter, and use the full available space. A 64 GB stick on USB 3.0 takes about 40 minutes at 25 MB/s. If the summary says something like “14.9 GByte of 64 GByte tested without errors”, the drive is a 16 GB part with a lying controller and the seller owes you a refund.
The identical scam runs on memory cards: how to spot a fake microSD card.
One price check avoids most of it: a genuine 64 GB USB 3.0 stick from SanDisk, Kingston or Samsung sells for roughly BDT 700–1,100 in Dhaka, and a “2 TB” drive at BDT 600 is impossible at current NAND prices.
Ejecting: when the warning is real and when it is theatre
Windows 10 from 1809 onward, and all of Windows 11, default removable drives to “Quick removal”, which turns off write caching — pulling the stick without ejecting will not corrupt a file that already finished copying. The risk is the file still in flight, so watch the copy dialog close rather than hunting for the tray icon.
The default is not guaranteed. Check Device Manager > Disk drives > your drive > Properties > Policies: if “Better performance” is selected, megabytes can still sit in RAM and ejecting is mandatory. On macOS, press Command-E; on Linux, run sync before udisksctl unmount -b /dev/sdb1.
If “file or directory is corrupted” appears after a bad pull, run chkdsk E: /f from an elevated Command Prompt, swapping E: for your letter. That repairs the directory table, not a half-written file.
Pick the filesystem on purpose: FAT32, exFAT or NTFS
The wrong choice produces a failure that looks like a broken drive. FAT32 refuses any single file larger than 4 GB, so an 8 GB wedding video stops at the 4 GB mark with “the file is too large for the destination file system” — a limit baked into the format, not a fault.
- FAT32 — read by everything, including car stereos, older TVs, printers and games consoles. Cap: 4 GB per file, 32 GB partition if you format it from Windows’ own dialog.
- exFAT — no practical file-size ceiling, works on Windows 7+, macOS 10.6.5+ and most Android phones with an OTG adapter. Some older car head units and the PlayStation 4 will not mount it.
- NTFS — the right pick for Windows-only archives and files above 4 GB with permissions intact. macOS mounts it read-only without paid software.
To format: right-click the drive in File Explorer > Format > choose the file system > tick Quick Format. Untick it only when you suspect bad blocks; a full format rewrites every sector and takes an hour on 64 GB.
Encrypt it before it leaves the house, not after
A stick carrying scanned passports or salary sheets should not be readable by whoever finds it in a taxi. BitLocker To Go, part of Windows Pro and Enterprise, encrypts removable drives with AES-XTS: right-click the drive > Turn on BitLocker, set a password, and save the 48-digit recovery key somewhere other than the drive. On a machine without BitLocker support the volume mounts read-only, which is fine for handing documents to a client.
Microsoft’s documentation on BitLocker and BitLocker To Go covers the recovery-key handling, which is the part people skip and later regret. If you use Windows Home or need the same stick to open on Linux, VeraCrypt is free and cross-platform. Expect encryption to cost 5–10% of transfer speed on USB 3.0 — noticeable only on very large copies.
Encryption protects a lost drive, not a malware-laden one: scan unfamiliar sticks, and switch off AutoPlay under Settings > Bluetooth & devices > AutoPlay so a planted file cannot launch itself.
The habits that actually prevent data loss
Keep one folder per project with a date in front — 2026-03-invoices rather than New folder (2) — so a full stick sorts by name instead of by memory. And never let a stick hold the only copy of anything: it is a courier, not a backup.
Store drives at room temperature; a glovebox in April reaches 55–60°C and flash retains data poorly when baked. Avoid editing video directly from a stick, and if one starts throwing “delayed write failed” errors or drops to 3 MB/s, copy everything off and retire it. For the file-loss side of the same subject, see USB flash drive tips to stop losing files.
