Hello there!
I am sorry for the trouble you had, the 'To Do Card' option is to check any pending workflows for PDF files like Review, views, and Sign.
You can disable the To Do card option through the registry settings, for detailed information, you may refer to the help article, look under Home Screen and Startup Lockable Settings
The registry path is HKLM\SOFTWARE\WOW6432Node\Policies\Adobe\(product name)\(version)\FeatureLockdown
Specifies whether to show To Do Cards in the Recent Tab view
When set to 1, To Do cards do not appear in the Recent tab. Possible values include:
0 or null: Show cards for unaccepted workflows (reviews, views, and sign).
1: Hide cards for unaccepted workflows (reviews, views, and sign).
Feel free to update this discussion if you have any further query.
Thanks,
Anand Sri.