The Unfinished Buddha is so-called because of its incomplete nature; the hands of the statue are not fully carved, the right arm is longer than the left and one of the shoulders is bigger than the other.
[1] Van Erp's action didn't go without negative critics by some archeologists, they commented that he should put it back inside the stupa instead of leaving it outside the temple.
[1] In 1994, Prof. Soekmono wrote an archeological journal in which he told the true reason why he didn't put the statue back inside the main stupa.
The reason is that they would have had to partially dismantle the stupa which was restored by Van Erp, and that that action would clash with the spirit of reconstruction of that time.
[1] Now the statue can be seen at Karmawibhangga Museum which is built on the ground of the Archeological Park created around Borobudur during the restoration sponsored by the Indonesian government and UNESCO that began in the 1970s.
[3] Although the right hand of unfinished Buddha statue looks rather like a squared-off mitten, it was clearly meant to display the bhūmiśparsa mudrā (mudra of touching earth).
[6] By based the research on Avatamsaka Sutra, some scholars assumes that the unfinished Buddha in the center of Borobudur is the symbol of Shakyamuni.
[6] Thus I have heard, At one time the Buddha was in the land of Magadha, in a state of purity, at the site of the enlightenment, having just realized true awareness'.The theory is supported by the fact that the unfinished Buddha statue shows the bhūmiśparsa mudrā, a mudra which was displayed by Sakyamuni to call the earth as his witness for his enlightenment.
It is unimaginable "that after having been shown the utmost future we are to be drawn back again to the toiling earth, to the things that our thoughts on the first gallery, the preaching Çakyamuni".