having a very weird issue with a user who is unable to save or edit calendar appointments in her own calendar. User has an Office 365 mailbox and is using Outlook 2019 on a Windows 10 workstation. Issue is present on multiple workstations using the users Outlook Profile, I also have tried using Outlook 2016, i did notice in 2016 Outlook ill get an error in the task bar, it triggers Event ID 25 which says "Sorry, something went wrong. You may want to try again. 2019 just sits there with no error and the appointment window won't close when clicking save, if you close the appointment window you will be asked to save but nothing happens when you click yes and the window stays there. Issue is present with cache mode on or off. What im seeing is the appointments that are unable to be Edited\Saved all have a "Follow Up By" with a date right above the Subject line, items just have Follow up with no date. If i view the calendar in list view you can see all the calendar items that did have a follow up by in red text if the date has passed.
I've tried adding the Task view to the calendar list to see if there is a Flag for follow up, but there is none, the to do list shows no items. Ive,tried tagging the email for follow up then clearing the tag. It makes the red text go away but still doesn't allow the item to be edited or saved.
This user has over 10,000 calendar entries and blowing her calendar away isn't an option. What is more distributing is that new appointments the user is creating sometimes have this "Follow Up by" i can't figure out whats causing it. User will use Outlook and the iPhone Default Mail app to create appointments. To repeat calendar items that DO NOT have this "Follow Up" message can be edited and saved just fine. Anyone ever seen something like this? Am i dealing with corrupted items? Any help would be greatly appreciated.
Here's an example of the "Follow Up By" message that shows on the calendar appointment enter image description here
Here's an example of the calendar items in list view, notice the appointments that are in Red have the follow up by message, items in black do not and can be edited or saved without issue. If i add the Flagged column to this view, none of these red items show they actually have a flag. If i use that column to flag one of the red items, then clear the flag the follow up message on the appointment will be removed, however i will still be unable to edit or save the appointment. To note that none of these calendar items appear in the todo list where a normally flagged email would appear. enter image description here
