Mailbox issue - not updating for all users - synchronization problem

Question

We have a shared mailbox currently being used by 7 users.

If I delete one email from inbox, the other 6 people will still be seing that email - is not synchonizing.
If I go to Outlook Online (OWA), I also will be seing the email there. And if I delete there, then is really deleted. But it goes to the mailbox deletion folder (and not mine, as it should be - same as outlook in desktop). Else, is really a time consuming using outlook online.

We have tried to Uncheck this box - so we wouldn't use the cache - the synchronization worked, but we were not able to do anything else (delete emails, categorize, flag, etc, we could only look at them).

ps: if we use the online outlook, everthing everyone does (categorize, delete, organize emails in folders) everyone else can see.

Any tips what do we do to Outlook (app - desktop) can back to work?

Here what else we have done so far

• clean all the rules and check if the behavior continues
• remove the shared mailbox from all users who have permissions and map again in Outlook

Thanks!!

• Oulook 2016

Answer 1

Hi @Jéssica Floriano ,
What's the version of your Outlook 2016(File>Office account>About Outlook), please first ensure that you have updated to the latest version of Outlook.

According to my test, the items in shared mailbox could be synced to server or other clients when I changed them on my Outlook 2016, so it seems to I couldn't reproduce your issue.
Did this issue occur only when you delete items on Outlook? Could it be reproduced if other users delete items in shared mailbox on their Outlook?

If the issue only happened to you, there may be any synchronization problem on your Outlook client. As I know, the corrupted data file may affect this issue, it's suggested to rename your data file(.ost) and restart Outlook to check if the issue has any difference(default location: C:\Users\Username\AppData\Local\Microsoft\Outlook).

If the issue still exists, corrupted data file may also cause it, please try to create a new profile and readd your account to test(Control Panel>Mail>Show profiles>Add>type a profile name>readd your account)

If the issue actually happened on every users' client, I'm afraid it may be related to the shared mailbox itself, Agree with michev, the size of mailbox may affect this issue, please first try to reduce the size to check. Also, in order to further analyze it, we could try to create a new shared mailbox and re-assign the permission to users for testing.

Hope your issue would be resolved soon.

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Answer 2

How large is the shared mailbox and how large are the profiles of the users trying to access it? What you are describing above look like "standard" issues with large/corrupt cache files, the best thing to do is to reduce the size as much as possible (using the Online Archive is the best option). Unchecking the Download shared folders checkbox will only have proper effect if you create a new Outlook profile, so you can try that as well. Or you can stick to using OWA, especially if the mailbox size is over 10GB.