"They lose their will and personality, but their motor skills are still instact, so they wander here and there."
A Wanderer is a Giftia whose programming has been corrupted after having accumulated 81,920 hours (approximately 9 years and 4.3 months) of service without being retrieved. Giftia who become Wanderers lose their memories and personality and only act on instinct. They do not even recognize their owners. Given this, it is also possible for them to assault humans and grow violent, especially when subjected to stressful situations.
After a Giftia has turned into a Wanderer, it is almost impossible to calm them down and simply deactivate them. When a retrieval deadline is missed, the Terminal Service assigned to a particular region is required to neutralize the Giftia-turned-Wanderer by any means necessary, often by force. The private security firm R. Security is also sometimes summoned to help in intercepting Wanderers. Devices such as the Virus Data Gun of SAI Corporation and combat weapons such as the M16s of R. Security may be used to destroy a Wanderer.
Unlike Giftias which have been successfully retrieved, Wanderers cannot be rebooted nor reactivated, and a new operating system cannot be installed in their body. It is due to this that people agree that having the Giftia you care for turn into a Wanderer is one of the most terrifying things that can happen.