Legacy (1.0) Character Cannot Use Company Chocobo

[Kirika-]

See:
https://forum.square-enix.com/ffxiv/threads/323092

If that doesn't correct the issue, as in recovering the Chocobo Whistle from a Calamity Salvager, then also double check that you are trying to summon it correctly:

1. Open the Character sub menu (round Character icon, lower right of screen)
2. Open Mount Guide
3. Access Tab #1
4. Your Company Chocobo will be the first tile, drag that out to a slot on a Hot Bar
5. Click (or button push if using a controller) that Icon to summon your mount

   NOTE: This only works in Open World and Residential areas, you can't summon mounts in city states and in most instanced areas.