Rufus Troubleshooting Guide: Fixing Error 0x00000015, Access Denied, & Formatting Failures
While Rufus is widely regarded as one of the most reliable USB preparation utilities on Windows, system conflicts, third-party antivirus utilities, bad flash memory sectors, and Windows security locks can occasionally cause operations to abort. Below is a structured diagnostic guide to solving each major issue.
Error: [0x00000015] The device is not ready
This error occurs mid-way or at the end of the extraction process when the operating system abruptly loses communication with the USB flash controller, or when a background process unmounts the volume while Rufus has an open file handle.
- Plug directly into motherboard I/O ports: Avoid front-panel case ports, unpowered external USB hubs, or keyboard pass-through ports. USB 3.0 controllers can draw temporary voltage drops that cause disconnects.
- Disable USB Selective Suspend: Open Windows Control Panel → Power Options → Change plan settings → Change advanced power settings → USB settings → USB selective suspend setting → Set to Disabled.
- Verify Flash Memory Integrity: Check the box "Check device for bad blocks" (1 pass) in Rufus before starting. If blocks fail verification, the flash controller is failing and the drive must be replaced.
Error: [0x00000005] Access Denied / Could not open drive
Windows error code 5 indicates an OS-level permission refusal. Rufus requires exclusive raw low-level write access to the physical disk sectors (`\\.\PhysicalDriveX`). If another software holds a handle, the operating system denies access.
- Windows Defender "Controlled Folder Access": In Windows Security → Virus & threat protection → Ransomware protection → If "Controlled folder access" is ON, it blocks raw disk sector writes. Whitelist Rufus or temporarily disable it.
- Third-Party Antivirus & USB Protectors: Bitdefender, Kaspersky, or Sophos frequently quarantine the autorun partition or lock new boot sectors. Temporarily disable real-time scanning during the flash process.
- File Explorer Windows Open: Ensure no File Explorer windows, command prompts, or disk management tools are open viewing the USB drive's drive letter.
USB Drive Does Not Appear in the Device Dropdown
By default, to safeguard users from accidentally formatting internal storage, secondary SSDs, or external backup hard drives, Rufus filters out fixed hard drives and USB HDDs/SSDs.
In Rufus, expand "Show advanced drive properties" (or press the key shortcut Alt + F), then check the box labeled:
"List USB Hard Drives".
Your external USB external hard drive or high-speed portable SSD will now populate in the Device list.
How to Reset a Corrupted or Stubborn USB Drive via DiskPart
If a flash drive is throwing corrupted GPT tables, unformatted RAW errors, or refuses to let Rufus write new boot sectors, cleaning the partition table via Windows native DiskPart will restore it to an empty state:
# 1. Open Command Prompt as Administrator and run:
diskpart
# 2. View all connected disks and identify your USB drive number (e.g. Disk 2):
list disk
# 3. Select your USB drive (CAUTION: Ensure you pick the right disk number):
select disk 2
# 4. Zero out all MBR/GPT tables and hidden partitions:
clean
# 5. Exit diskpart and launch Rufus:
exit
After running clean, unplug the USB drive, reconnect it, and launch Rufus. Rufus will detect the blank drive and format it fresh without conflict.