During the simulation, the robot does not move. In the previous version (2023), the same station does not have this problem.
and what is the output box at the bottom of the screen saying?
Few things that silently break simulation motion when opening an old station in RS 2025:
Event Manager - go to Simulation > Event Manager and check if SimulationStart is still mapped to your entry routine. This linkage drops on migration and the program just never starts. Most common cause.
VC in Manual mode - after migration the virtual controller sometimes wakes up in Manual. Open the virtual FlexPendant in RobotStudio and switch it to Auto mode.
RobotWare version mismatch - if RS 2025 rebuilt the VC with a different RW version, some motion config options can differ. Check Controller > Properties.
What is the Output window showing when you hit Play? That will point straight to the issue.