The presets formats changed between Guitar Pro 6 and Guitar Pro 7.5.
If you want to import former Guitar Pro user sound presets in Guitar Pro 7.5 you can use the following workaround:
- Open Guitar Pro 7.5
- Go to the Track Inspector
- Select the name of the sound for the current track
- Select Manage user sounds presets... from the dropdown menu
- A new window will pop.
Either File Explorer on Windows or the Finder on macOS.
The right location should pop up automatically.
- Place your presets in the My effect Chain presets folder.
Access and load your presets from the Effect Chain section of the Track inspector as shown below: