I think I might done something stupid so that I encounter such an error. Firstly, I am using MacBook Pro (late 2013), running on the latest Mac OS Mojave (ver.10.14.5).
Today I was trying to save some space on my SSD because it's running on low storage. I was using CleanMyMac app to help me clean up some space (I found that a lot of Mac users actually won't recommend to use such a cleaning app, since it could harm your devices and yes it actually did). I was using the CleanMyMac tools a bit unusual from my daily usage. So I believe that this is the roots of my problem.
What I can remember from the usage is, I was altering some of launchpad files, preference panes files, and deleting sudo file(?) using CleanMyMac app. After taking such an action, the first symptoms I got is the Mail app icon is missing. At first, I think it might be a temporary problem that can be solved with rebooting the Mac. Yet, what I found after rebooting is as you can see in the picture below.
The worst problem is that, none of my app is working and the Mac Menu Bar is disappeared. Any last opened apps became unresponsive.
What should I do? Is it possible o fix the problems by reinstalling the OS? If yes, then I have another problem, since currently my storage are insufficient to reinstall the OS via Safe Boot mode because I can't even open finder to delete some files to get more storage.