Start here: Run the User Diagnostic Tool for an affected user. It will often tell you straight away why that user wasn't imported.
If you still need to find the cause, work through these checks:
Check whether you ran a Test Sync instead of a Manual Sync
If you've just run a sync and no data was imported, you may have run a Test Sync.
A Test Sync doesn't change any data in usecure. Instead, it emails you a sync summary showing the changes the next manual or automatic sync would make, so you can check your configuration first. You can tell a Test Sync summary email apart because its subject line ends with "Test Results".
To fix this: Go to the Microsoft 365 Integration settings page, scroll to the Manual Sync section and run a manual sync.
Make sure users have a first and last name
Every user needs a first and last name. The sync will exclude any user it can't find these for.
Users with both the First name and Last name fields filled in Microsoft Entra ID (formerly Azure Active Directory) will be included.
If those fields are empty, the sync splits the Name field to work out the first and last name.
If the Name field is a single word, the user will be excluded.
To fix this: Add a first and last name to the affected users in Microsoft Entra ID, then run the sync again.
Check users' email domains match your account's domain lock
If your usecure account has a domain lock, users whose email addresses don't match that domain will be blocked from the sync.
To fix this: If your company uses more than one email domain, the domain lock needs to be lifted. Contact support to arrange this. If you only use one domain and believe all your users are on it, go to the next check.
Check how the sync sets users' email addresses
The sync can set users' email addresses in different ways. You can see which method you're using on the "How would you like the sync to establish a user's email address?" step of the configuration wizard.
User Principal Name Only (recommended): This is the default for new setups. The sync only uses the User Principal Name (UPN) field in Microsoft Entra ID as the user's email address. This suits most Microsoft 365 tenants.
Original: If your sync was set up before March 2022, it may still use this method. The sync checks the Email / SMTP Email Address (mail) field first, which you'll find under Contact Info in Microsoft Entra ID, and only uses the UPN if mail is empty. If the mail and UPN values don't match, users can be imported with the wrong email address or excluded entirely. For example, a user whose mail value doesn't match your domain lock will be excluded, even if their UPN does.
All methods are subject to your domain lock, if one is enabled.
To fix this: If you're using the Original method and users are missing or have the wrong email address, you can change the method on that step of the configuration wizard. If you're not sure which method suits your data, contact support before changing it.
Make sure users have the UserType property set
Older user accounts may not have the UserType property set. The sync needs this field to bring users over.
To fix this: Follow our guide on how to add the UserType property to missing user accounts, then run the sync again.
Confirm you authorised the correct Microsoft 365 tenant
This only applies to Managed Service Providers setting up the sync on their internal account or on a customer's account.
If you see the error No viable users loaded from API, you may have authorised the wrong Microsoft 365 tenant during setup. In that case, none of the users returned will match the account's domain lock.
To fix this: Reauthorise the sync with the correct tenant using the Sign In with Microsoft button on the Microsoft 365 Integration settings page.
Still missing users?
If you've worked through all the checks above and users are still missing, contact our support team and include:
the email address of at least one affected user
the result of the User Diagnostic Tool for that user
your most recent sync summary email, if you have one
This lets us check your sync logs straight away without needing to ask you for more information.