The procedure below outlines the steps for removing the Sendplus History for Mac users:
1. Ensure the Sendplus application is not running.
2. Navigate to the following folder: "/Users/your_user_name/Library/Application Support/Sendplus/ " (note: this is a hidden folder)
3. As a precaution make a copy of the "history" folder.
4. Delete the "history" folder.
As a last step relaunch Sendplus and try to log-in.