1. Go to Inky Help menu-->Troubleshooting-->Delete Inky data
2. Manually delete the Arcode folder.
On Windows: Select "Local Disk" C:
Then drill down to users-->your username-->AppData-->Local
On Mac: Type in ~/Library/Application Support/
You will see a folder called "Arcode". Right-click on this folder and move to trash.
Note: Make sure Inky is not running while manually clearing your cache.
Note: This problem is frequent with Outlook accounts.
Likely cause: This may be due to a failure of confirmation that the email was already delivered, somewhere in the email delivery process. This may be at any point between the first sending from your computer, or the final delivery on the server.
Proposed Solution: Clear your cache .
Sometimes antivirus software on your computer or local network can trigger your email software to behave as if it has not sent a message, when it already has. This is especially true of Outlook. You may need to look into this further if it becomes a common issue. If the problem is occurring outside of your local network, unfortunately, it may be impossible to determine where the duplication occurred.