Sync update between GAL on Exchange online and Outlook app on computer

Question

How often GAL sync between Online Exchange and Outlook application on phone or PC please?

Is it possible to amend the sync period or increase?

Is it possible to reduce the sync time?

Is there a way to do via PowerShell or I have to do on the Exchange online website?

Answer 1

Hi @IT ,

I add some external contact to our online exchange, but it takes hours to reflect on the offline GAL. I would like to know how long does it usually take to show up or sync offline GAL with Online Exchange please.

Thanks for the clarification, now I am understanding that you are actually talking about the Offline Address Book (OAB).

According to this document, the Offline Address Book (OAB) /or Offline Global Address List in Exchange Online are generated every 8 hours.

And Outlook client itself will update the OAB at least once every 24 hours. So, taken in the round, it's expected that it may take 24 to 48 hours for the GAL changes to reflect on the OAB in Outlook client.

While we don't have control over the generation/update time period of OAB, which is 8 hours as aforementioned, you can manually download the latest copy of the OAB in Outlook via the Send/Receive tab, select Send/Receive Groups, and then select Download Address Book.

So, it has been more than 9 hours (the generation process can take up to 1 hour) since you added the new contacts, but users still cannot see them in Outlook OAB, you can try manually downloading OAB in Outlook using steps above and check the result.

Here's a thread about a similar question for your reference:

Global Address List (GAL) refresment interval in Microsoft 365 Outlook

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Answer 2

Hi @IT ,

How often GAL sync between Online Exchange and Outlook application on phone or PC please?

The Global Address List (GAL) is a direct view of the current mail objects and it's usually updated automatically across devices right after the change occurs.

Is it possible to amend the sync period or increase?
Is it possible to reduce the sync time?
Is there a way to do via PowerShell or I have to do on the Exchange online website?

NO. We have no control over the update of address lists in Exchange Online (The Update-AddressList cmdlet or Update-GlobalAddressList isn't available in Exchange Online PowerShell), so it's not possible to modify the "sync time" by either PowerShell or via EAC.

In case you encounter issues that recipients that should appear in an address list do not, you would need to change the required property value for those users to a temporary value, and then back to the value that's required by the address list. For more details, you can refer to:

Use Exchange Online PowerShell to update address lists

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