You plug the drive in, the router page still says "No USB device", and the share never appears. In most cases the drive is fine — the router is rejecting it for one of a few very specific reasons.
A router is much pickier than a PC. Your computer reads almost any drive in any format with any power supply; a router has a small list of supported file systems, a weak USB power budget and strict ideas about drive enclosures. When the USB page shows nothing, work through these checks in order — the first two fix the majority of cases.
The classic dead end — the sharing service is on, but the router cannot see the drive at all.
Unplug the drive from the router and connect it to a PC. If the PC also cannot see it, the problem is the drive or its cable/enclosure, not the router — try a different cable and listen for clicking sounds (clicking means the drive itself is failing; rescue data before anything else). If the PC sees the drive normally, note its file system in Properties — you will need it in the next step.
This is the number one cause. Most routers support NTFS and FAT32; some also support exFAT or HFS+, and Linux-based firmware may add ext2/ext3/ext4. A drive formatted in something the router does not know is simply invisible to it. The manual or the router support page lists the supported formats for your exact model. If yours is unsupported, copy the data off on a PC, format the drive to NTFS (best general choice for Windows homes), copy the data back and reconnect. Remember FAT32 cannot hold a single file larger than 4 GB — a common reason movie files fail to copy later.
Router USB ports often supply less power than a PC port. A 2.5-inch hard drive that spins up happily on a laptop may half-start and vanish on a router. Fixes: use the drive's own power adapter if it has one (all 3.5-inch drives need it), use a powered USB hub between router and drive, or try a shorter, thicker cable. If the drive light blinks in a pattern or the drive keeps clicking softly, power is almost certainly the issue.
Many routers cap supported drive capacity (older models often stop at 2 TB) and do not guarantee compatibility with multi-bay enclosures or drives with unusual controllers — TP-Link states this plainly in its own troubleshooting guide. A huge desktop drive in a cheap multi-bay box may never appear. Test with a simple pen drive: if the pen drive shows instantly, the router and settings are fine and the big drive/enclosure combination is the problem.
Some routers disable USB sharing when the port is assigned to another job (printer sharing or a 3G/4G dongle mode) — set the USB mode back to storage. Then check for a firmware update for your exact model on the manufacturer website; USB compatibility fixes are a very common firmware changelog item. After any change, restart the router and give it a full minute before judging.
Watch the video to see a drive connect and appear on the router page the way it should — useful for spotting exactly where your setup differs.
▶️ Watch Full VideoNo — detection has worked in that case. The sharing service or folder selection is off. Go to the USB section, enable network sharing (SMB), and choose at least one folder to share.
Some routers offer a format button, many do not. Formatting on a PC is safer and lets you verify the drive at the same time. Remember formatting erases everything on the drive.
Yes, USB is backward compatible, but the speed drops to USB 2.0 levels. The drive should still be detected — if it is not, power or file system is the more likely cause.