After uvision became none responsive.
Opening the project, I discovered my entire last working file is blank empty. all last changes are gone.
Any way to restore it?
There is no recovery by default, but uVision offers several "File & Project Handling" features at the "Configuration" tab; see:
Related:
"How to turn on autosaving in Keil."
https://community.arm.com/support-forums/f/keil-forum/52086/how-to-turn-on-autosaving-in-keil