Recommended Free Tools
If a USB flash drive or external disk isn’t appearing on your phone, first check whether the phone supports the drive-and-adapter connection, then check the connection, file access, format, and power. The steps differ for Android and iPhone. If you mean your phone is connected to a computer but the computer can’t see it, use the separate phone-to-computer troubleshooting section below.
First, identify which USB connection is missing
“USB not showing up” can describe two different problems:
- A drive connected to the phone: You want to open files stored on a flash drive or external disk using the phone.
- A phone connected to a computer: You want the computer to show the phone’s files.
The instructions below begin with a drive connected to the phone. Compatibility depends on the exact phone model, its port, the adapter and the drive—not just whether the connectors fit. For a precise diagnosis, note your phone model, the phone and drive connectors, and whether the drive works on a computer.
If a drive is connected to your phone
Check the adapter and physical connection
- Seat the drive and adapter fully, and check for visible damage to the connectors or phone port.
- Make sure the adapter supports data or OTG, not charging alone. A matching connector does not guarantee that an adapter or drive is compatible.
- On Android, check that your specific phone model supports USB OTG. Samsung’s Galaxy USB troubleshooting guidance recommends checking model support and, when possible, testing another compatible drive and adapter.
- If available, try a known-good compatible drive and adapter one at a time. This can help distinguish an accessory problem from a phone-port problem.
On Android, open the drive in a file manager
Google says Files by Google can access USB storage on Android 7.0 and later. Connect the drive, open the Files by Google app, tap the “USB available” notification if it appears, and tap Allow. The drive should then appear under Storage devices. If the notification does not open, disconnect and reconnect the drive. Other manufacturers’ file managers and menu names may differ.
#1 Best Overall
- USB-C 2-in-1 storage OTG: The Lexar JumpDrive Dual Drive D40E features USB Type-A and Type-C connectors in a slim, portable form factor for easy device compatibility
- Transfer speeds up to 100MB/s: Based on internal testing, performance may vary depending upon the host device, interface, and usage conditions. 1MB=1,000,000 bytes
- Plug and Play: Widely compatible with USB Type-C smartphones, tablets, laptops, Macs, and traditional Type-A devices, no software installation required. The 360° swivel design allows for easy switching between connectors without the hassle of losing a cap
- Durable & Compact: The Lexar D40E USB memory stick features a metal enclosure, withstands temperatures from 0° to 50° C (32°F to 122°F), and is lightweight at 26g with dimensions of 70.4 x 16.9 x 11.7mm
- Security & Warranty: Securely protects files using an advanced security software solution with 256-bit AES encryption. Backed by a Lexar 3-year limited warranty
On iPhone, unlock the phone and check Files
Connect the storage device using a compatible connector or adapter, and make sure the iPhone is unlocked. Open Files, tap Browse, and look under Locations. If Locations is not visible, tap Browse again. Apple’s external-storage instructions describe the supported connections and how to find a connected device.
Check the drive’s format and partition layout
A drive can connect physically but remain unavailable if its format or layout is unsupported. Apple requires a single data partition for iPhone external storage and lists APFS, encrypted APFS, macOS Extended (HFS+), exFAT (FAT64), FAT32, and FAT as supported formats. Samsung’s Galaxy OTG troubleshooting guidance specifies FAT32 or exFAT.
Rank #2
- USB-C STORAGE ON THE GO: This sleek drive is supported by Samsung NAND flash and is incredibly compact to fit in the palm of your hand; Count on reliable performance and fast transfer speeds while staying compact
- PERFORMANCE WITH SPEED: No need to choose between performance and reliability; Experience a fast, powerful flash drive that transfers 4GB files in just 11 seconds with up to 400MB/s USB 3.2 Gen 1 read speeds and is backward compatible with USB 3.0/2.0
- MODERN MEETS ICONIC: The ultra-sleek USB-C drive looks as good as it performs; Featuring a reversible plug, the Type-C inserts into your devices seamlessly every time; Transfer large files with style and ease
- ALWAYS CONNECTED: USB-C is compatible across devices, including laptops, tablets, phones and cameras, with enough space for 63,730 photos or maximum 12 hours of 4K video; With up to 256GB of storage space, this pocket-sized thumb drive comes in handy wherever you go
- TOUGH & TRUSTED: Files stay secure, no matter the terrain; Samsung's flash memory technology makes the Type-C a trustworthy drive to store your valuable data; It's waterproof, shock-proof, magnet-proof, temperature-proof, and X-ray-proof body, plus it's backed by a 5-year limited warranty
Do not reformat the drive as a first step: formatting erases its contents. Back up the files first, and check the support instructions for your exact phone before changing the format or partition layout.
Consider whether the drive needs more power
Apple notes that “External hard drives often require an external power source when used with iPhone.” For a USB-C iPhone, Apple identifies a powered USB hub as an option when the drive does not power itself. For a Lightning iPhone, Apple identifies a Lightning to USB 3 Camera Adapter connected to a USB power adapter. These are iPhone-specific options, particularly for external hard drives; they are not a universal fix for every phone or flash drive.
Rank #3
- USB-C 2-in-1 storage OTG: The Lexar JumpDrive Dual Drive D40E features USB Type-A and Type-C connectors in a slim, portable form factor for easy device compatibility
- Transfer speeds up to 100MB/s: Based on internal testing, performance may vary depending upon the host device, interface, and usage conditions. 1MB=1,000,000 bytes
- Plug and Play: Widely compatible with USB Type-C smartphones, tablets, laptops, Macs, and traditional Type-A devices, no software installation required. The 360° swivel design allows for easy switching between connectors without the hassle of losing a cap
- Durable & Compact: The Lexar D40E USB memory stick features a metal enclosure, withstands temperatures from 0° to 50° C (32°F to 122°F), and is lightweight at 26g with dimensions of 70.4 x 16.9 x 11.7mm
- Security & Warranty: Securely protects files using an advanced security software solution with 256-bit AES encryption. Backed by a Lexar 3-year limited warranty
If your phone is connected to a computer
If the computer cannot see a phone connected by USB, check the phone’s USB connection mode rather than treating it as an attached flash drive. Samsung says Galaxy devices starting with One UI 8.0 default to “Charging phone only.” For file-transfer tasks, its instructions say to choose “Transferring files / Android Auto.” This setting applies to the phone-to-computer connection; it is not a general fix for a flash drive plugged into a phone. Labels and steps can vary by device and software.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.When to seek device support
If several known-good, compatible drives and adapters fail on one phone, or the phone’s port appears damaged, contact the phone maker’s support or repair service. If you suspect debris in the port, avoid poking inside it with metal tools.
Quick Recap
Best Value
- 【Important】: Default format of the usb flash drive 128gb is exFAT as this is the format recognized by the smartphones and tablets. These 128gb thumb drives are only compatible with C-Port enabled mobile phones & computers only. While formatting the usb flash drive dual type c usb 3.0 OTG keep a check on the drive format
- 【Easy to Use】: Directly plug the 2-in-1 USB flash drive and play, no need to install any software. The jump drive is easy to be recognized by computer, laptop, notebook, PC, car audio, speaker, smart TV, vidoe projector etc
- 【Fast Speed】: High-speed USB 3.0 flash drive for fast data transfer, backwards compatible with USB 2.0 easy to complete the storage and transport functions. USB 3.0 and Class A chip help you transfer a 4G movie from the thumb drive to your smartphone in about 40 seconds, and reverse transfer in 2 mins to save memory for your smartphone with Type C port.Save your time
- 【Good Compatibility】: Dual connectors USB type C + USB 3.0. Support windows 7 / 8 / 10 / XP / 2000 / ME / NT Linux and Mac OS, compatible withUSB 3.0 & USB 2.0 backwards USB1.1. Support videos formats: AVI, M4V, MKV, MOV, M P4, MPG, RM, RMVB, TS, WMV, FLV, 3GP; AUDIOS: FLAC, APE, AAC, AIF, M4A, MP3, WAV
- 【OTG Function】:Support nearly all mobile phones which support OTG function,and very easy to operate
Rank #4
- 2 in 1: USB C + USB 3.0, 32GB usb c flash drive has dual ports, usb 3.0 port is applied to all devices which have usb 3.0 interface and usb c port is widely used in all Android smartphones with OTG function
- High Speed USB 3.0: Read speed up to 90 MB/s, Write speed up to 30 MB/s, the speed of USB 3.0 interface is faster than USB 2.0, save time to wait, increases work productivity. Note: Speed will be limited if you use the USB key in the USB 2.0 interface
- Large Compatibility: The USB 3.0 Connector is compatible with USB 3.0 & USB 2.0 backward USB 1.1 devices, such as Laptop, Desktop, Car Audio, Tablet, TV, Speakers, Projector. USB-C port is compatible with all Android Smartphones
- Expand Storage: Good performance in storing, transferring and sharing digital data with families, friends, colleagues, customers. It can expand the capacity of smartphone, you can watch movies or share pictures when you go on vacation with your family
- Note: Make sure your smartphone is equipped with OTG function and need to open OTG function in Settings when you plug memory stick, then you can transfer easily data bewteen different devices
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
