Steve Wozniak, who co-founded Apple with Steve Jobs, has predicted cataclysmic problems in the future with cloud computing.
Mr Wozniak is widely seen as the grandfather of the modern PC, having invented the Apple II machine, and was scathing in his criticism of the cloud, where users upload their music, books, emails and other files onto remote computer servers.
Rather than store information on a PC's hard drive, the cloud is rapidly becoming the normal place to keep personal information and files.
Mr Wozniak said: "I really worry about everything going to the cloud. I think it's going to be horrendous. I think there are going to be a lot of horrible problems in the next five years."
His main concern stems around the ownership of people's personal information. "I want to feel that I own things," he said. "A lot of people feel, 'Oh everything is really on my computer,' but I say the more we transfer everything onto the web onto the cloud, the less we're going to have control over it."
Mr Wozniak's attack on the cloud is particularly startling given the fact that he remains an employee at Apple, which sees the iCloud as one of its greatest growth areas.
He is not on his own in his view. In technology circles, concerns are regularly raised about the fact that, however much people may encrypt their information, it remains "out there" on the web with the potential for being hacked into.
While users think they have ownership of their information, in some cases they hand ownership rights over to the company hosting the server. But Richard Graham, partner of law firm Edwards Wildman Palmer, said: "You are not signing any intellectual property away or losing control over things you should otherwise own."