Daniel 10:7

‘And I Daniel alone saw the vision, for the men who were with me did not see the vision, but a great quaking fell on them and they fled to hide themselves.'

This does not necessarily mean that they saw nothing. The very approach of the glorious figure may well have terrified them before he appeared in full view, so that they ran for cover and hid themselves and thus missed the full glory of the vision. (Running for cover suggests that they saw something). On the other hand it would not be the only time when a vision was only seen by one man while his companions were only aware of something strange and the sound of a voice (compare Acts 9:3 onwards).