I'm sorry to hear that kwin_x11 is crashing. Let's see if we can figure out what's going on. Could you provide a bit more detail? For example:
1. When did the crashes start happening?
2. Are you seeing any error messages?
3. Have you made any recent changes to your system or installed any new software?
4. What version of KDE and kwin_x11 are you using?
These details will help pinpoint the issue.