Android Can't Access USB Drive — How to Fix It

You connected a USB drive via OTG and nothing happens — or you get a "Permission denied" error when you try to open files. Here are the actual causes and how to fix them.

Quick Answer

Most USB access failures are caused by: wrong OTG adapter (cable-only adapters don't pass data), wrong format (NTFS on stock file manager), or Android 11+ permissions not granted. Fix these first.

Fix 1 — Grant Full Storage Permission to AnExplorer

On Android 11 and later, apps need explicit permission to access external storage. When AnExplorer first detects a USB drive, it should ask for access. If you dismissed that prompt:

1. Settings → Apps → AnExplorer → Permissions
2. Files and media → Allow management of all files
3. Disconnect and reconnect the USB drive
4. Open AnExplorer — the USB drive should now be accessible

Fix 2 — Check the OTG Adapter (Most Common Cause)

Not all USB-C to USB-A adapters support OTG data transfer. Some are charging/power adapters only:

• Look for an OTG adapter labeled USB OTG, USB Host, or USB 3.0 OTG
• Adapter from a phone box or a no-brand Amazon listing often doesn't include data lines
• Test with a different adapter — this fixes the problem in ~40% of cases

If you're on Micro-USB: use a Micro-USB OTG adapter (these usually work — Micro-USB OTG is well-standardized).

Fix 3 — Your Phone Might Not Support USB OTG

Check before troubleshooting further:

• Your phone specs should mention USB OTG or USB Host
• Most phones from 2014+ support OTG — but budget phones from certain OEMs disable it in software
• Test: Settings → About phone → look for USB OTG in the feature list, or download the OTG Checker app

Fix 4 — The Drive Format Isn't Supported by the Stock File Manager

Android's default file manager (Files by Google, Samsung My Files) has format limitations:

If you're using an NTFS or ext4 drive and your stock file manager says "unsupported format" or shows the drive but no files, switch to AnExplorer — it natively reads and writes NTFS and ext4 without root.

Fix 5 — The Drive Needs Too Much Power

USB drives draw power from your phone's USB port. For spinning hard drives (HDDs) this can exceed what OTG provides:

• Flash drives: fine — draw < 100 mA
• 2.5" portable HDDs: sometimes fails — draw 200–900 mA
• 3.5" desktop HDDs: always fails — need external power

Solutions for HDDs:

• Use a self-powered USB hub between the HDD and phone
• Or switch to a USB-C SSD (e.g. Samsung T7) — low power draw, fast

Fix 6 — The Drive May Be Corrupted

If the drive works on a PC but not on Android:

1. Connect the drive to a Windows PC
2. Open File Explorer → right-click the drive → Properties → Tools → Check
3. Run the error checking — fix any errors
4. Safely eject from PC, then try on Android again

If error checking reports "cannot fix errors" or finds bad sectors: the drive may be failing. Back up your data immediately and replace it.

Fix 7 — Reformat the Drive

If the drive is otherwise new or working fine but Android won't read it:

Reformat to exFAT (recommended for Android compatibility):

1. Connect to Windows PC → File Explorer → right-click drive → Format
2. File system: exFAT → Start
3. Or use AnExplorer on phone: tap and hold the drive → Format → exFAT

Warning: Reformatting erases all data on the drive. Only do this if you have a copy or the drive is empty.

Checking Permissions on Android 13+

Android 13 introduced granular media permissions. If you're on Android 13 or 14:

1. Settings → Privacy → Permission manager → Files and media
2. Find AnExplorer → select Allowed for all files (not just media)

USB Drive Shows in AnExplorer But Files are Missing

This is common with FAT32 drives where files were deleted on Windows but not properly flushed:

1. Connect drive to Windows → open command prompt
2. Run: chkdsk D: /f (replace D: with your drive letter)
3. This repairs the file allocation table — missing files may reappear

Related Guides

• Transfer Files to USB Drive — full OTG transfer guide
• SD Card Not Showing — similar fix for SD cards
• Open Files on Android TV from USB — TV USB access fixes