Knowledge

ERROR_UNABLE_TO_EJECT_MOUNTED_MEDIA - 4330 (0x10EA)

Unable to eject the medium because it is in a drive.

Updated: Feb 21, 2026

Technical Background

The ERROR_UNABLE_TO_EJECT Mounted_MEDIA error code, with the numeric value 4330 (0x10EA), is a specific file system error that indicates an attempt to eject media from a drive was unsuccessful because the medium is currently in use or cannot be ejected due to its current state.

Error Details

This error typically occurs when a user or application attempts to remove a storage device, such as a CD/DVD, USB flash drive, or external hard disk, while it is still being accessed by the system. The operating system prevents this action to ensure data integrity and prevent potential corruption of files.

Common Causes

  • Invalid Parameter Values: Incorrectly specified parameters in the API call that attempt to eject the media.
  • Incorrect Object Type: Attempting to eject a non-media object, such as a folder or file, which is not supported by the system.
  • Exceeding Limits: The system may have limitations on how many drives can be ejected simultaneously, and this error could occur if those limits are exceeded.
  • Corrupted Data: If the media itself is corrupted, it might prevent ejection due to potential data integrity issues.

Real-World Context

This error commonly occurs in scenarios where a user tries to remove a storage device while an application or system process is still accessing files on that device. For example, attempting to eject a USB drive when a file explorer window has the drive open, or when a backup operation is in progress.

Is This Error Critical?

The criticality of this error depends on the context. If the media cannot be ejected, it may prevent other operations from completing successfully and could lead to data loss if not resolved.

How to Diagnose

  1. Review Operation Context: Ensure that no application or system process is currently accessing files on the drive.
  2. Validate Parameters: Check the parameters passed to the API call for ejecting media, ensuring they are correct and valid.
  3. Confirm Object Types: Verify that the object being ejected is indeed a storage medium and not another type of file or directory.

How to Resolve

  1. Correct Parameter Usage: Ensure all parameters in the API calls are correctly specified.
  2. Adjust Operation Context: Close any applications accessing files on the drive before attempting to eject it again.
  3. Restore Data: If data corruption is suspected, back up important files and seek professional assistance if necessary.

Developer Notes

  • Always check for active file handles or processes that might be using the media before attempting to eject it.
  • Implement retry logic with appropriate delays between attempts to handle transient issues.
  • Provide user feedback indicating why ejection failed and what steps they can take to resolve the issue.

Related Errors

  • ERROR_MEDIA_EJECT_REQUEST_FAILED (0x8007063A)
  • ERROR_MEDIA_IN_USE (0x8007054F)

FAQ

Q: Why does this error occur?

A: The error occurs when the system detects that the media is currently in use or cannot be safely ejected due to its current state.

Q: How can I prevent this error from occurring?

A: Ensure no applications are accessing files on the drive before attempting to eject it. Close any open file explorer windows and wait for all operations to complete.

Summary

The ERROR_UNABLE_TO_EJECT_MOUNTED_MEDIA (4330, 0x10EA) error is a specific file system error that indicates an attempt to eject media from a drive was unsuccessful due to the medium being in use. This error can be diagnosed by reviewing operation context and validating parameters, with resolution involving adjusting the operation context or correcting parameter usage.