Hi,

Ugh that's not good. 

Is this an Outlook issue happening with an Exchange server too or an Exchange+SM issue ? (MAPI I guess?).

Kind regards

MAPI + SM. I havent got any Exchange running to test.

Did you just lose access? Are the shares missing data or just permissions? Is it all shared calendars including domain and user level, or is it limited to just domain level shares? Were those shares visible again after reattaching to them? The tickets you've referenced are older tickets that both reference the first ticket number you noted and only affected Outlook clients with multiple MAPI accounts set up - is that still the case?

It started behaving like it did in the tickets mentioned. Dissapearing and couldnt add at again.

The behaviour has changed. I have updated the server with the latest patches from MS.

I recommend you submit a new ticket on this referencing the ones from last year, that should help tie everything together on our end documentation-wise. Please include as many details as you can on testing steps you've taken so far, what errors you see (if any), and any patterns or clues you've seen while testing as all of these details help paint a clear picture of what is happening. With no other users chiming in here my suspicion is that this has something to do with the data or environment itself so these will be critical to understand. 

I dont see any errors.

After a outlook restart then shared calendars are no longer viewable.

Unfortunately we'll need to get more details from you in a ticket Brian. Your original tickets reference having multiple MAPI accounts setup in a single Outlook client whereas this post references shared calendars. To ensure we're on the same page and looking at the same areas a ticket is going to be our best bet.