Are you having issues with doing a character copy to the PTS in SWTOR? You’re not alone if you’ve been experiencing a bug with this process but some SWTOR players have found a fix that seems to be working for everyone who tries it.
Take off all of your companions’ gear and put them in cargo bay, then transfer your character. Quick and easy fix!
Some players are reporting that taking off the ship’s parts may also work.
If you’re getting the message “We were unable to process your requested move of characters to Public Test Server. This account has reached the 12 character maximum on the server.” Then this fix will not help you. The probably with this is when you already have characters on both the open and the closed test servers. BioWare should be fixing this one but if we come across a fix, we’ll update to let you know.
Source: SWTOR official forums