Resolution when there is a failure to open the Excel file. Possible reasons : the file is corrupt, the file is already used by another process or you don't have permissions to open the file.
Approach #1: If applications are killed at the start of automation, try providing some delay of 60 secs and check. If it works, try to decrease the delay and decide on the amount of delay that works best in the considered case.
Approach #2: If the above solution does not work and if using Unattended automation,
- Go to the project in Studio-->Project Settings-->Disable Starts in background
When running Background Automations via Unattended Robots, using Microsoft Office applications such as Word, Excel or PowerPoint might not work properly as they have been built to run in User-Session, meaning that they need an interactive desktop session and user profile.
For additional information on how Office 365 Products work with Server Sessions(session 0), see the Server-side Automation of Office document from Microsoft.