Hi hertels,
Welcome to Microsoft Community.
May I ask whether your computer is Windows 10 or Windows 11 operating system?
If this dialog box is displayed after the system is started, it indicates that a script file (possibly the residue of third-party software or virus threat) will automatically run after each startup. Now that the file has been deleted, the message "Can't find the XXX file" will be displayed.
In Wiindows 10, you can right-click the taskbar, open the "Task Manager" and go to the "Startup" page to check whether there is the 533786.vbs boot item or some strange name boot item, click disable them and restart the computer to see if it does not pop-up again.
In Windows 11, you can press Esc+Shift+Ctrl to open the task manager. The subsequent operations are the same as those in Windows 10.
If the above methods still do not solve the problem, you can try a clean boot and see if simply excluding the service or process associated with the script file can be completely resolved.
Disclaimer: A “clean boot” starts Windows with a minimal set of drivers and startup programs. It helps to determine whether a background program is interfering with your game or program and to isolate the cause of a problem.
These steps of "clean boot" might look complicated at first glance. However, to avoid any trouble for you, please follow them in order and step-by step so that it will help you get you back on track.
If there is anything not clear, please do not hesitate to let me know.
Best Regards,
Manson - MSFT | Microsoft Community Support Specialist