Every time when opening MS Outlook user gets the following warning:
Outlook Data File
The file C\Users\<username>\AppData\Local\Microsoft\Outlook\Internet Calendar Subscriptions.pst cannot be found.
The issue was resolved by going to Outlook > Account Settings > Account Settings > Data Files and removing the offending Internet calendar file.
If you had subscribed to any Internet Calendars (i.e. Google Calendar) you may need to re-add them.
Windows 10 Pro
MS Office Outlook 365