How Do I Fix Photo Dates on an External Drive?
Working directly on a USB drive or portable disk, and the one thing to check first.
You can work straight off an external drive. The only real difference is speed, since USB is slower than an internal disk, so a large library takes longer than it would locally.
Check the drive's format first. Very old drives formatted as FAT32 cannot hold files over 4GB, which matters for video, and they store dates less precisely. exFAT or NTFS avoid both problems.
Takeout JSON Metadata Fixer reads and writes any folder you point it at, including one on an external drive, and can export the organised result straight to another drive or a USB stick. Free for your first 500 photos.