Firstly, it should be noted Caphtor is mentioned in Egyptian, Mari, Neo-Assyrian, and Israelite records, but is not mentioned in the Hittite or Greek records.
In the Egyptian records, it is first mentioned in the 12th Dynasty, and is mentioned well into the reign of Thutmose III. In the reign of Thutmose III, Keftiu was considered a land of the West (i.e. west of the Nile, in other inscriptions, Punt/Eritrea is mentioned as being a land of the East). Keftiu was also mentioned in a nonsensical topographical list of Ramesses II.
In the Bible, Caphtor is portrayed as the land of the origin of Philistines (Deut 2:23, Jerem 47:4, Amos 9:7), and as a coastland. The Philistines were called Cherethites/Cretans by the Amalekites in 1 Sam 30:14. Caphtor was also confused with “Coptos”, at the end of the Wadi Hammamat, or, perhaps, with the Greek name “Egypt”, and was therefore identified as an Egyptian, and not a Mediterranean (Javanite) land, in Genesis 10.
In the Mari records, Kaptara is mentioned as having merchants buying tin. The King of Hazor is also mentioned as sending gifts to the King of Kaptara. Alashiya (Cyprus) is also mentioned in the Mari records as a copper-producing country. In the Neo-Assyrian “Sargon Geography”, Sargon of Akkad was said to conquer “Anaku, Kaptara, Dilmun (in the Persian Gulf), and Magan (Modern Oman, considered to be at/near Egypt in Neo-Assyrian tradition).
Since the Bible and the Mesopotamian records offer no clues regarding the location of Keftiu, we have to use the Egyptian records. Since those never place Keftiu in parallel with Alashiya, Keftiu is suggested to not be at Cyprus. The phrase “Keftiu and the Isles of the Great Green” in the tomb of Rekhmare, suggests Keftiu is in the Aegean area. Kaptara is shown in the Mari records to be ruled by a monarch. This is consistent with Caphtor being Crete, with its four administrative centers of Knossos, Zakros, Phaistos, and Malia.
It is therefore clear that Biblical Caphtor can be reasonably identified with Crete, and identifications in Cyprus and elsewhere are unlikely.