What does Appdata mean? What files can be deleted by appdata?

means that it includes files needed when the system program is running. It is not recommended to delete!
What file is appdata, can I delete it?
appdata is the application data in xp. There are custom settings in various programs, including the program can be personalized and can not affect the user files, temporary folders, quick start folder, etc. It is Important system folder, it is recommended not to delete, delete the problem.
If the hard disk space is tight, you can delete the AppData\\Local\\Temp\\* file.
Application Data: XXX\\application data is the meaning of application data, application data, this folder stores the MSI installation files of some software, generally do not need to delete them, because some software will have this need. If you really need to delete it, because the data is generally not used, just an automatic backup, but if the software goes wrong, you have to fix it. And it is recommended to make a backup before deleting. In case there is a problem, you can restore it at any time!
XXX\\local setting\\application data is some data generated when accessing the network. It includes some personal habits of the Internet and some personal settings of the client.
The personal settings of the game after deletion and the general settings of the PC will be deleted. The Quick Launch folder is a shortcut for storing the quick launch bar.