Disadvantages of cloud computing

Looking for more disadvantages of cloud computing. This is for my college project and seminar. Thanks for sharing

Data Security is the biggest disadvantage of cloud computing.

This is for companies and individuals, storing data in an unknown location invites data security challenges.

I need more information about cloud computing disadvantageous. My final year project is a cloud computing project. Please help me

Major disadvantage of cloud computing are follows:
Unsuitable for mission critical applications
Data Security (In case of public Cloud)
Legacy systems are expensive or impossible to migrate on to cloud