Partition label signatures on a device should be wiped when formatting
There are times when the Format...
option in Nautilus will fail due to a conflict with partition label signatures on a flash drive. This most commonly happens when the flash drive has had an ISO imaged to it, making it have an ISO 9660 signature. The solution is to use the wipefs -a $DEV
command on the device before formatting it, which will ensure that the device has a clean slate.