How do I determine if a macro successfully ran at the scheduled time?

As the last line of the macro script, insert the Email Send command. Send an email to yourself. The email can contain a date and time stamp with a simple message saying the macro ran successfully.

Or insert a Log Message command as the last line of the macro script. Log a message to a text file with a date / time stamp and a simple message saying the macro ran successfully. Review the file when convenient.