I have unlocked HK-51 with all the mission, after that I decided to make another character. The problem is, I still do not have it in my crew list, I bought it with cartel coins, but it says I have already unlocked it. I have no clue about what's happening.

I'm not sure but I think you have to max out HK's affection to unlock him for all characters.

The ability to get HK-51 via legacy and actually having HK-51 are 2 different things.

 

You need to do the quest once per faction to unlock the legacy to buy HK 51 on alt.

You need to purchase HK 51 when you have the legacy perk unlocked on alts to actually get him (1 mil credits) or do the quest again when you hit 50.

You do Not have to unlock him with both factions to get him. I unlocked him on an imp toon & bought him through legacy for a pub toon @ lvl 1. You also do not have to Max his affection.

You do Not have to unlock him with both factions to get him. I unlocked him on an imp toon & bought him through legacy for a pub toon @ lvl 1. You also do not have to Max his affection.

 

This, you guys above should really check your facts before you start telling people the wrong information....last thing new people need is bad information

LordAlset is correct, you do NOT need to max his affection or unlock him on both sides. To gain him on a new toon you need to be sure to select the appropriate unlock on the character perks tab, as there one for imperial and one for repub. Not sure why the need for the 2 unlocks, but that's the way it is.

Since it is a legacy unlock, if you roll a new toon on a different server, then you will need to go thru and unlock him via the quests.

Regarding the OP's comment, not sure what is going on there unless he somehow hit the unlock for the wrong faction? I have unlocked him on lvl 1 toon myself and he is available right away by opening the crew skill window with "N". Just need to summon him.