If you are trying to locate a friend in-game using the relocation menu, there's a few things to keep in mind.
1) You will only see users that are your friend on the platform you're currently using. This means:
- If you are playing on KIXEYE.COM, you will only see KIXEYE.COM friends
- If you are playing on Facebook, you will only see Facebook friends
- If you are playing on Steam, you will only see Steam friends
- If you are playing on Android, you will only see Google+ friends
- If you are playing on iOS, you will only see Game Center friends
2) If you have a friend added on the platform you're currently playing from but you still don't see them, then their planet is likely full. You will need to pick a different friend to relocate to or your friend will need to move to an emptier planet.
3) If you have a friend added on the platform you're currently playing from and the friend has already relocated to an emptier planet so you can find them, but you still don't see them, your profile may have security settings in place that are preventing our API from making calls to the friends list for your platform. This especially happens on Steam. Simply make your profile public instead of private and it should clear up the issue.
4) If you are not comfortable making a profile public, try simply joining the same Alliance as your friend. This will allow you to use the Relocate to Alliance Member feature instead.