Please start the client and then read last client log file and look for errors.
%AppData%\TS3Client\logs
- Then update your graphics card driver (driver shouldn’t be older than 2 years) and Windows 10 or 11.
- Install client again Index
- Try start client with start parameter
-safemode
or-force-opengl-soft
- Maybe client opened outside viewable area on your screen. There are ways to move the app.
Some Programs Are Displayed Off the Screen - Microsoft Support