It sounds like you've hit a frustrating snag, but I may have a couple of suggestions to aid troubleshoot this issue. First, ensure that the Screenshot Captor application itself is set to run as administrator. Right-click the shortcut in the Startup folder, go to Properties, then Compatibility, and check "Run this program as an administrator." Sometimes permission issues can hinder an application from launching at startup.
Secondly, it might be worth checking if any antivirus or security software could be blocking the application from running at startup. Occasionally, these programs flag benign applications as potential risks and prevent them from executing properly.
If these steps don’t resolve the issue, another approach could be to create a task in Windows Task Scheduler instead. This method provides more control over how applications launch at startup and can sometimes bypass issues encountered with the Startup folder method.
Give these steps a try and let us know how it goes!