Disappearance of activities

At present I am using community edition, So everytime I open my existing xaml file most of the activities are lost in the whole sequences, and to run it I have to install package every single time( Mostly Database and Web activities).
So Is this happening due to any bug in my system or is this because of using the community edition?

Hi @Priyanka_Rani,
Please tell which version of CE do you have? Have you tried to reinstall it?