In order to backup my PS3™, in preparation for replacing the hard disk drive with a larger SSD I have laying around my desk, I needed a FAT32 formatted USB disk. Windows 10 will only allow disks larger than 32GB to be formatted as exFAT (or NTFS), which the PS3™ does not support.

According to

32GB is the maximum partition size limit using the FAT or FAT32 file system format on Windows. That said, FAT/FAT32 can actually format up to 16TB hard drives and most operating systems support up to 2TB

I know I have definitely used FAT32 with 2TB disks under Windows 98SE in the past.

Fortunately it was easy to format my 64GB USB flash drive as FAT32 with FAT32 Format. No install required, just download and run the very small executable. Returning it to the PS3™, the drive now showed up when I went into the backup tool in System Settings.