Hello, 

This message error means that the path of  odoo-server-16.exe changed in windows and cannot be found (perhaps you changed the name of the odoo file or its path). To fix this problem, you need to check the service configuration: 

1 Open the Services app in Windows and locate the odoo-server-16 service. 

2 Right-click on the service and select Properties. 

3 Check that the "Path to executable" field is pointing to the correct location of the odoo-server-16.exe file. ( if this path dos not exist make sure to find the correct location for odoo-server-16.exe and change it )

Thanks