Hi @ Webber
Welcome to our forum!
Does the error occur recently? Did you perform any specific actions before the error occurred?
Based on my research, when I save the calendar events to the files I do not have access to, the error occurs. It is suggested that you may try to save the calendar event to another File Explorer you have access and to see if the error persists.
If the error persists, considering data file corruption, it is proposed that you create a new profile, re-add your account to the new profile and check if the same issue still occurs.
Hope it helps!
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