It doesn't, in fact no software at the moment covers Metro Apps.I don't think SBIE supports Windows Apps from Store.
Did anyone of you guys tested it against malware ?
Keep in mind that the more advanced malware codes know how to "recognize" when they are executed in a sandbox (or in a virtual environment) and self-terminating almost immediately.Did anyone of you guys tested it against malware ?
By default settings , you are right; if with customized settings, the malware can't connect outside the sandbox.Also, Sandboxie prevents writing to the real system (on the filesystem and the registry), but NOT the reading, and it doesn't prevent the malware from communicating with the outside: if you have personal data on the PC you are at risk.
Sandboxie is great for any application that you use daily; browsers, email and messaging clients. You can run File Explorer under SBIE supervision, so any apps and files opened from the Downloads folder will be isolated. And it's useful for testing out legitimate software you may not want to keep.
SBIE has a greater purpose rather than being used to run malware. It's secure and proven to be solid protection against unwanted system changes..