Your USB drive can have free space and still reject a large file because of FAT32
Checking the filesystem can explain the error before buying another drive, but changing the format requires a backup and a compatibility check.
The drive has room. The file still will not copy. A large video can run into FAT32’s per-file limit while leaving a perfectly impressive amount of free space behind.
Microsoft’s filesystem comparison lists FAT32’s maximum file size at 4 GiB, a rounded presentation of the familiar boundary. Its exFAT column permits much larger individual files. Drive capacity and the size of one file are separate limits, which is how a roomy cupboard can still have a door too narrow for the thing going inside.
That gives the error a useful first check. Inspect the USB volume’s filesystem and the size of the file that failed. A small document succeeding while one large recording fails is a reason to examine this limit before blaming the connector, the cable or the poor thumb drive.
Apple’s Disk Utility format guide includes ExFAT among formats compatible with Windows. It distinguishes those choices from APFS and its Mac-oriented features. Sharing between a Mac and Windows PC is one reason exFAT enters this conversation.
The format choice still has to include every device that will read the drive. A television, camera or older appliance may impose its own requirements. A file that finally copies from the computer has only passed the first half of the job if its destination cannot read the resulting volume.
Reformatting erases the existing contents. Before considering that change, copy valuable files somewhere else and verify that the copies open. The only copy of a family recording has no business volunteering as a filesystem experiment (even for science).
On a Mac, the relevant tool is Disk Utility. The safe sequence begins by identifying the external device carefully, then checking what it contains and what the destination supports. The actual erase operation should wait until both checks are complete. A similar-looking internal volume is a very expensive wrong click.
If the destination requires FAT32, keeping the existing format may be necessary. The right next move is then to find an output or transfer method the destination explicitly supports. Renaming a large file will not change its size limit, however persuasive the new filename sounds.
The Microsoft table also shows that exFAT and NTFS differ in features beyond file size. For a simple shuttle drive, cross-device reading may be the important row. For other uses, a reader should check the required permissions or resilience features rather than assuming every larger-file format is interchangeable.
The practical result is a diagnosis with a clear stopping point. Check the current format, establish the destination’s support and protect the data before making a change. A successful copy afterward should be followed by a read on the intended device; that is the output the reader actually needs.
The cupboard was big enough.