How to Update the Global Address List (GAL) in Outlook and Exchange

If you don’t know what a Global Address List (GAL) is, it’s simply a list of employees’ contacts within a company. However, updating the GAL is hectic and time-consuming, especially as the organization grows.

The Global Address List (GAL) is Exchange’s directory of mail-enabled recipients. When someone says the GAL is ‘not updating,’ the problem may be in the directory itself, the server-generated Offline Address Book (OAB), or the local OAB copy used by classic Outlook in Cached Exchange Mode.

Those are different layers. Updating GAL membership does not automatically mean that a classic Outlook client has downloaded a new OAB, and downloading an OAB in Outlook does not change who belongs in the GAL. The correct fix depends on where the delay is occurring.

CiraSync solves a separate mobile-contact problem: it can use the GAL as a source and sync selected directory contacts into targeted user mailboxes so those contacts can become available to Outlook and supported mobile contact workflows. It does not replace Exchange GAL administration or OAB generation.

How do we avoid the same consequences for your organization? We need to update the Global Address List regularly.

Let’s see the correct steps to follow!

TL:DR;

‘Updating the GAL’ can refer to GAL membership, server-side OAB generation, or the OAB downloaded by classic Outlook. Troubleshoot them separately.

For Exchange Server, Update-GlobalAddressList updates GAL membership, while Update-OfflineAddressBook forces a one-time OAB generation. Current Exchange Server uses OABGeneratorAssistant settings for recurring OAB generation.

For Exchange Online, Update-GlobalAddressList is not available and Microsoft generates OABs every 8 hours. Classic Outlook users can manually download the OAB after a newer copy is available.

New Outlook for Windows does not use Cached Exchange Mode, so the classic Download Address Book workflow does not apply.

CiraSync does not modify Exchange GAL membership. It uses the GAL as a source and syncs selected contacts into targeted user mailboxes for Outlook and supported mobile contact workflows.

 ‘Updating the GAL’ can mean three different things

Layer	What it controls	Server/admin action	User/client action	Environment
GAL membership	Which recipients are included in the Global Address List.	Exchange Server: Update-GlobalAddressList. Exchange Online: Update-GlobalAddressList is not available; address-list membership is based on recipient filters and recipient properties.	None. Outlook cannot change GAL membership.	Exchange Server and Exchange Online
OAB generation	The downloadable snapshot of address lists used by classic Outlook in Cached Exchange Mode.	Exchange Server: Update-OfflineAddressBook can force a one-time OAB generation. Exchange Online generates OABs every 8 hours and does not expose the on-premises update cmdlet.	None until a newer OAB exists on the service/server.	Exchange Server and Exchange Online
Classic Outlook OAB download	The local OAB files on a user’s computer.	No server-side membership change occurs.	Classic Outlook: File > Account Settings > Download Address Book, or Send/Receive > Send/Receive Groups > Download Address Book.	Classic Outlook with an Exchange or Microsoft 365 account

Diagnostic rule: use Outlook on the web to check whether the expected person or change is visible in the online directory. Microsoft recommends this as an OAB troubleshooting step. If the change is visible on the web but not in classic Outlook, the problem is likely in OAB generation or the client’s cached OAB rather than GAL membership.

How to Refresh the Offline Address Book in Classic Outlook

These steps refresh the Offline Address Book downloaded by classic Outlook. They do not change GAL membership on the Exchange server.

1. Open classic Outlook.

2. Select File > Account Settings > Download Address Book. Depending on the Outlook build, you can also use Send/Receive > Send/Receive Groups > Download Address Book.

3. Leave ‘Download changes since last Send/Receive’ selected for an incremental download. Clear it if you specifically need a full OAB download.

4. Select the appropriate address book if more than one is available, then select OK.

Important: Cached Exchange Mode is not available in new Outlook for Windows, so the classic OAB-download workflow does not apply there.

New Outlook for Windows note

Microsoft states that Cached Exchange Mode is not available in new Outlook for Windows. New Outlook has its own offline feature, but the entire Global Address List is not available while offline. Therefore, do not tell new Outlook users to look for ‘Download Address Book.’ If a directory change is missing while they are online, verify the directory-side change in Outlook on the web and troubleshoot the server/service layer.

How Long Do GAL and OAB Changes Take to Appear?

There is no single end-to-end ‘GAL update time’ because GAL membership, OAB generation, and Outlook’s local OAB download happen at different stages.

• Exchange Online: Microsoft states that offline address books are generated every 8 hours. A user’s classic Outlook client must then download the newer OAB before the local cached view reflects the change.
• Exchange Server Subscription Edition: Exchange Server Subscription Edition inherits the OABGeneratorAssistant behavior from Exchange Server 2019 CU15, including the default 8-hour generation cycle. Administrators can change the interval using a setting override.
• Exchange Server GAL membership: Update-GlobalAddressList starts the membership update process; Microsoft states that completion may take several hours.
• Exchange Online GAL/address-list membership: Update-GlobalAddressList and Update-AddressList are not available in Exchange Online PowerShell. Membership is based on recipient filters and recipient properties, and Microsoft provides a separate property-update workaround when expected recipients do not appear in an address list.

How to Automatically Sync GAL Contacts to User Mailboxes and Phones

CiraSync does not change who belongs in the Exchange Global Address List or force Exchange to regenerate an Offline Address Book. Instead, it uses the GAL as a contact source and syncs selected directory contacts into targeted Microsoft 365 user mailboxes. Those mailbox contacts can then be available in Outlook and supported mobile contact workflows.

1. Log in to the CiraSync dashboard.

2. In the Contact Lists pane, select the + option to create a contact list.

3. Choose Global Address List as the contact source type.

4. Open Collections and select the desired contact source or collection.

5. Select NEXT.

6. Select the target user or users for the sync configuration, then select NEXT.

7. Enter a name under Provide Contact List Name.

8. Choose the Contacts destination or create the preferred Contacts subfolder.

9. Configure optional settings such as Sync Contact Groups, Populate Outlook Auto-Complete List, and Retain obsolete items as required.

10. Select SAVE.

11. Return to the CiraSync home dashboard.

12. Select Update Cache in the Sync Status pane and run SYNC NOW for a manual sync.

Best Practices for Managing the Outlook Global Address List

1. Automatically Update Your Global Address List

I cannot stress this enough – automatic updates are the way to go.

Here are the main benefits of automatically updating the Global Address List:

Benefit	Description
Automated scheduled updates	CiraSync Enterprise can run automated contact synchronizations multiple times per day, reducing the need for users or IT to perform repeated manual contact updates.
Consistent contact distribution	Administrators can use the GAL or other supported sources to distribute selected contacts to targeted user mailboxes.
Better mobile contact availability	Synced mailbox contacts can be made available through supported mobile contact workflows, helping users identify and reach coworkers without manually creating each contact.
Centralized administration	IT can manage contact sources, targets, sync settings, and schedules from the CiraSync dashboard.

2. Communicate GAL Changes to Users

It’s essential to keep your team in the loop whenever you add, update, or delete GAL contacts. Send a quick email or post an announcement in your company chat to let everyone know about GAL sync and how to access updated contacts.

Here is a template for communicating changes to a team or organization:

You can use this email template if you are running a GAL maintenance:

3. Do Regular Audits to Ensure Accuracy and Completeness

Like any database, a GAL accumulates outdated entries over time. Consider scheduling regular audits to identify and remove inaccuracies and keep them lean and mean. This will improve the quality of your data, save space, and speed up syncs.

3 Common Problems People Encounter When Updating the GAL

Even if you follow best industry practices when syncing your GAL, things may not always work how you want. Here are some common problems you might encounter when updating the GAL.

1. Delayed Synchronization

The GAL doesn’t automatically sync in real-time across all systems and devices. It updates every 24 hours for On-Premises Exchange Servers and 24-48 hours for Microsoft 365/Exchange Online.

Also, while delays usually range from a few hours to 24 hours, unexpected factors (like server load or network issues) occasionally cause longer delays.

Solution

The solution is to ask admins to adjust GAL update intervals for the Microsoft Exchange Server by using a Powershell command like this one:

Set-OfflineAddressBook -Identity "Default Offline Address Book" -Schedule "Sun. 2:00 AM"

Replace «Default Offline Address Book» with the name of your specific OAB and adjust the schedule according to your needs.

For Office 365/Exchange Online, admins can encourage users to manually sync their address book in Outlook or clear their cached GAL using Outlook in cached mode.

2. Missing or Inaccurate Contact Information

So, you’ve gone into trouble updating your GAL, but users can see the new changes. What gives? Maybe you forgot to save your changes. Be sure to save everything before updating your GAL. If you did everything right, you could force a manual update.

3. Duplicate Entries

Every contact has been duplicated, somehow. Nothing clutters your organized GAL like a bunch of duplicates, with no one knowing who’s who. To deal with the issue, you can perform regular audits or simply use a tool like CiraSync that helps you detect and remove duplicates automatically.

Frequently Asked Questions

Why did Download Address Book not fix a missing user?

Downloading the OAB only refreshes the local classic Outlook copy. If the user is not present in the online directory, the problem must be fixed at the Exchange or directory layer first.

How can I tell whether the problem is the online directory or my Outlook cache?

Check Outlook on the web. Microsoft recommends verifying the GAL there during OAB troubleshooting. If the expected change is visible on the web but not in classic Outlook, investigate OAB generation or the local OAB download.

How often is the Offline Address Book generated in Exchange Online?

Microsoft states that Exchange Online offline address books are generated every 8 hours. Classic Outlook must still download the newer OAB before its cached view reflects the change.

Can I force Exchange Online to run Update-GlobalAddressList?

No. Microsoft states that Update-GlobalAddressList and Update-AddressList are not available in Exchange Online PowerShell.

Can I force an OAB update on Exchange Server?

Yes. On-premises Exchange provides Update-OfflineAddressBook. Current Exchange Server also uses the OABGeneratorAssistant for the recurring generation schedule.

Does new Outlook for Windows have the same Download Address Book option as classic Outlook?

No. Microsoft states that Cached Exchange Mode is not available in new Outlook for Windows. Its offline feature is different, and the full Global Address List is not available while offline.

Does EWS retirement affect native Outlook OAB downloads?

Microsoft’s Exchange Online EWS retirement applies to Exchange Web Services. OAB generation and download are separate Exchange address-book functions. EWS starts being disabled globally in October 2026 and is fully disabled in April 2027. Applications that depend on EWS should follow Microsoft’s migration guidance.

Does Exchange ActiveSync turn the GAL into native phone contacts?

Exchange ActiveSync synchronizes mailbox data such as contacts, but the organization’s GAL is not automatically converted into a set of native device contacts. CiraSync addresses this by syncing selected directory contacts into user mailboxes, which can then participate in supported mobile contact workflows.

Does CiraSync update the Exchange GAL itself?

No. CiraSync can use the GAL as a source and synchronize selected contacts to targeted mailboxes. Exchange GAL membership and OAB generation remain Exchange administration functions.