While primarily used for Windows ISOs, changing the boot selection drop-down to "All files" allows you to select and flash a DMG file to a USB drive. If you want to troubleshoot this further, let me know: What version of Windows are you using? What macOS version is the DMG file you are trying to write? Have you tried another USB flash drive ? Share public link
Type list disk to find your USB drive's number (e.g., Disk 2).
If you have access to a working Mac, plug the USB drive in and use Disk Utility to erase it, ensuring the format is MS-DOS (FAT) or ExFAT with a GUID Partition Map . Summary Table: Troubleshooting Steps Run as Admin Grant elevated permissions. Close Explorer Release file-level locks. Diskpart Clean Remove partition locks. Disable AV Stop scanning locks. Transmac Drive Has Been Locked By Another Program
You are trying to flash a macOS installer or access an Apple-formatted drive on Windows. Suddenly, TransMac stops you with a frustrating error:
Let's diagnose the possible root of the problem. The issue can usually be traced back to one of these causes: While primarily used for Windows ISOs, changing the
Press the , type cmd , right-click Command Prompt , and select Run as administrator . Type diskpart and press Enter .
Windows and macOS use different file systems (NTFS/FAT32 vs. APFS/HFS+). When you plug a Mac-formatted drive into Windows, the OS gets confused. It may try to "fix" the drive or repeatedly prompt you to format it, which keeps the drive "busy" and prevents TransMac from gaining exclusive access. If these steps didn't work, tell me: What are you using? Are you using a USB 2.0 or 3.0 drive? Did you get a specific error code ? Have you tried another USB flash drive
To resolve the lock, the user must systematically identify the process holding the handle and terminate it.
If the quick fixes do not work, use these methods to force Windows to release the drive.
TransMac requires exclusive access to the USB drive to format it to a Mac-compatible file system (like HFS+ or APFS) and write raw image data. The error happens when: is browsing the drive. Antivirus software is scanning the drive. Another disk tool is accessing the device. The drive was not properly ejected previously. Top Solutions to Fix TransMac Drive Locked Error Follow these solutions in order to resolve the issue. 1. Close All File Explorers and Programs
: Right-click the TransMac icon (on your desktop or in the Start Menu) and select "Run as Administrator" . This is perhaps the single most effective fix. For a permanent solution, right-click the icon, select Properties → Compatibility tab → check "Run this program as an administrator" .