To format a USB drive with multiple partitions on Windows 11, you can try using the built-in Disk Management tool, but first, you need to delete the existing partitions. However, if the options are grayed out, you can try using a third-party tool like Qiling Partition Manager or MiniTool Partition Wizard, which can help you delete the partitions and format the USB drive. Alternatively, you can also try booting from a Linux live USB and using the built-in formatting tools to format the USB drive. If none of these methods work, you may need to consider purchasing a new USB drive.
The format option may be greyed out in Disk Management because it doesn't allow direct formatting of unallocated space, requiring a partition to be created first, and also has limitations in formatting larger USB drives to FAT32.
You can turn to another third-party format utility, Qiling Disk Master, to format the disk.
To format your unallocated USB, you can use Qiling Disk Master, which allows you to create a partition on the unallocated space and select the desired file system format during the process. Simply download Qiling Disk Master and follow its steps to format your USB.
Step 1. Start Qiling Disk Master on your PC.
Step 2. To create a new partition on your USB drive, right-click on the unallocated space in the main window and select "Create."
Step 3. Modify the new partition's partition size, file system, and label.
Step 4. Choose "Proceed" to create a new partition on your USB.
After using Qiling Disk Master to format the USB drive, you can successfully format your USB drive. Additionally, with the help of this tool, you can create partitions on a USB drive or merge partitions on a USB drive.
Hope this tool and this guide can help you!