Modern Outlook truncating Distribution List expansion...

[psydii]

Just come across this, and wondered if anyone else has seen it?

 

We needed to email a large number of people (internally) about a thing. A distribution group exists that contains all these people. But it also includes 6 people who should not receive the email.

So we do what we always do, expand the distribution list in Outlook and then remove the specific email addresses we don't want to send the email to.

 

Except today, when we can't find one of the addresses to remove from the list!

 

Copy paste into Excel and we find we are about 75 addresses short. A quick PowerShell query of the AD group and all the members are present.

 

(obvious solution to the problem in front of me is to copy paste out of the PowerShell query, remove the 6 and paste the result back into outlook, which is fine for me, but less fine for a DH or HoY)

 

I've checked and confirmed a sample of the missing members are mail enabled and have expected licenses for 365.

Just before I expand the group in Outlook, the banner warning that this email will be sent to about 258 people which agrees with what powershell reports.

But on expansion 75 are missing.

 

What is going on?!

[Iain.Faulkner]

Daft response, potentially, the 75 that are missing. Are they hidden from the Global Address List?

[psydii]

Daft response, potentially, the 75 that are missing. Are they hidden from the Global Address List?

Good question, and potentially a thing that could have happened (certain automations hide accounts in certain circumstances). Just checked, but no, they are not hidden (msexchhidefromaddresslists is not present) and they have the same entries in the showinaddressbook property.

[Iain.Faulkner]

Bother, we had exactly the same scenario you've described and I thought I was going round the bend. The only thing we found was that the accounts that were missing were hidden from the address lists in Office 365. We made them visible and they immediately reappeared.