Cloud computing disadvantages being experienced or talked about in industry are
Ultimate dependency on internet connection. If no internet then user have no option but to wait, unlike in current case where users can continue some or other process.
Data security – Though cloud vendors take utmost care of data security in cloud computing however this is still a point of contention for many if not all.
Frequent Changes - As cloud computing is still in transformation phase so any drastic change in services may adversely impact hosted application and ultimately the business.
Cost – Though at first, its easily assumed that clod computing solutions are far cost effective compared to on premises setup. However if migration planning and requirements are not done properly then it may go other way round.