Author: Adam Fowler

“This page wants to run the following add-on…” won’t go away in Internet Explorer

In the last few weeks, I found that a lot of users were complaining about IE11 on Windows 10, and the prompt “This page wants to run the following add-on” with the add-on name, and the allow button:

This webpage wants to run the following add-on ‘Adobe Flash Player’ from Microsoft Windows Third Party Application Compon…

However, clicking the ‘Allow’ button, or using the drop down arrow to choose ‘Allow for all sites’ did nothing, and the prompt would show again and again.

I ended up working out this was due to the Add-On List GPO to list IE add-ons that was being used to manage the add-ons I wanted disabled or enabled https://docs.microsoft.com/en-us/internet-explorer/ie11-deploy-guide/enable-and-disable-add-ons-using-administrative-templates-and-group-policy

The policy explicitly states “The ‘Deny all add-ons unless specifically allowed in the Add-on List’ policy setting will still determine whether add-ons not in this list are assumed to be denied.”

However, since a recent update (either Windows 10 1803, or a recent security patch  – unsure which!), anything not listed in the Add-On List was being blocked. 

Adding an update to the list and allowing it with the ‘1’ value fixes the issue for that particular add-in, but it shouldn’t be working this way.

I even tried disabling the Group Policy setting ‘Deny all add-ons unless specifically allowed in the Add-on List’ but that made no difference. That policy also states: ‘If you disable or do not configure this policy setting, users may use Add-on Manager to allow or deny any add-ons that are not included in the ‘Add-on List’ policy setting.’

Something wacky’s going on – if I find out more I’ll update this post, but if you do use the ‘Add-On List’ GPO for Internet Explorer, be aware of this potential issue. You may need to list all your add-ins into the policy to avoid this.

I’ve also updated all my ADMX files for Win10 1803.

Users Managing Email Groups and Exchange Online

For a very long time, users have been able to manage email group members via the Outlook client. Going into the Address Book, finding the group in the Global Address list, going into Properties and choosing ‘Modify Members’:

From there, someone can add or remove members as long as they’d been added to the “Managed By” field against the object in Active Directory, as well as ticking the box “Manager can update membership list” below it.

Easy! Except, that no longer works if the user is in Exchange Online, and the Email Group is from on-premises AD rather than Azure AD/Office 365. It’s not supported. This problem has been around for a while, back in 2015 Perficent wrote about this same topic. The options given for managing these groups are:

  • Exchange Admin Center
  • Exchange Management Console
  • Exchange Management Shell

None of those are what you want your standard users touching in my opinion – although you can give someone access to the Exchange Admin Center and only see the distribution groups they own – but for me, I’m still on Exchange 2010 so this isn’t an option.  This leaves you with a few options:

1. Change all your email groups to Cloud based groups. If this makes sense for you, doing this will let the manager of a cloud based group add/remove members via the Outlook Address Book.
You can also look at changing distribution groups over to Office 365 Groups (which are also cloud based), which give a whole bunch of different features beyond a what a distribution group can do, while giving the same standard DG experience.

2. Make all requests come through to IT so you can make the changes yourself. Not great for anyone involved, as it’s double/triple handling something where the user could quickly do it themselves.

3. Create Dynamic Distribution Groups and let automation do it’s thing – which will work for some, but exceptions to rules and the inability to see who’s in a group can make this frustrating for some.

4. Provide another way for staff to change group members themselves.

I’ve gone with option 4 – as I’m a big fan of Adaxes which I’ve written about a few times on my blog before, and they have a nice way of giving users a web interface that only lets staff manage the groups they’re the owner of.

There’s other ways to do this as well of course and other 3rd party solutions that can expose ways of adding/removing members of a on-premises distribution group – but remember there could be up to a half hour delay in syncing the change from AD to AAD via Azure AD Connect. If possible, look at adding a trigger at the end of a group change to do a delta sync:

Start-ADSyncSyncCycle -PolicyType Delta

That’ll be the quickest way to get the change up quickly, as staff may be used to the change working immediately.

There’s a lot to consider on how you’ll manage this, so make sure it’s sorted before you migrate – or expect a lot more tickets going through your helpdesk.

Migrate a Single Mailbox Out of a Exchange Online Migration Batch

A few posts on this since it’s what I’m working on :)

It is possible to sync all your mailboxes from Exchange On-Prem to Exchange Online as a single batch, and then complete individual items – but it’s not obvious that this is even possible.

Normally if you start a migration, you can choose multiple mailboxes or use a CSV file to specify which accounts to start migrating – while specifying the option to manually complete the batch, so the actual migration happens when you want it to:

The problem is, once you’ve fixed any problems that arise and mailboxes are in a ‘synced’ state, there’s no visible way to complete a single mailbox – just the whole batch. That may not be what you want to do. You could work out a way to create a separate batch for every single mailbox you’re migrating, but there’s also a way to complete one mailbox at a time.

In PowerShell, once you’ve connected to Exchange Online, you can run the a command to see all the mailboxes syncing, and their status:

Get-MoveRequest

If a mailbox is ready to be finalised, it should have the status of ‘Synced’. This is different to the status of ‘Completed’, which occurs once the mailbox has been fully migrated across.

To trigger the completion of a single mailbox in a batch, use this PowerShell command:

Set-MoveRequest -Identity “mailbox name” -CompleteAfter 1

The mailbox will then do it’s final syncing and complete, without affecting the other jobs in the same batch. The -CompleteAfter parameter is supposed to set the delay before the request is completed in date/time format, but using the value ‘1’ seems to immediately trigger this.

Now you can do a single batch job, and selectively complete mailboxes as you choose – easy! 

(Note that there was an old method of doing the above by setting the variable SuspendWhenReadytoComplete to $false which no longer works)

Exchange Online Mail Enabled Security Groups

One of the things I’ve found out while migrating to Exchange Online was around access to shared mailboxes, and having to alter my methods slightly.

For Exchange On-Prem (Exchange 2010), whenever I created a shared mailbox I would control access with a security group. If the mailbox was called “Finance”, then I’d have an Active Directory Security Group called “Finance Mailbox Full Access” and give that group full access to the mailbox. Then, I’d add the staff that needed access to that group – meaning it was easier to track and manage who had access to what, particularly with nested group support so I could add a whole department in.

The extra win on this approach was around applying logic to the groups. When someone joined or left Finance, the user management process would ensure the user was added to a group for Finance. That would then feed into all the access that Finance were granted through the groups that single group was inside – and it works great. 

The good news is that this is still possible going to Exchange Online, my nested and automated systems can continue to work. However, some changes were required to make this work.

Firstly, any security group that is going to be added to an Exchange Online mailbox for access must be mail enabled. This goes against my personal best practice as I liked complete seperation of security groups and email groups, because I didn’t want to deal with scenarios where ‘All Finance need this resource, but I don’t want them to get the emails about the same resource’. Still, having a descriptive security group name should avoid that happening. 

This leads to another catch – to mail enable a security group, it has to be ‘universal’. In turn, that means every other group that those groups are inside also need to be universal.

For me this was easy, since all my security groups were cleanly in a single OU, and there was no impact to me on changing them to universal (check this for yourself though!)

Get-ADGroup -SearchBase 
“ou=Security Groups,ou=ABC,dc=com” | Set-ADGroup -GroupScope DomainLocal

After that, ,ail enabling an existing security group is easy with the PowerShell command:

Enable-DistributionGroup

I was actually able to mail enable all my Security Groups that granted mailbox access at once, by getting all the groups and filtering them down to only ones that contained the word ‘Mailbox’

Get-Group -resultsize unlimited | where {$_.name -like “mailbox“} | Enable-DistributionGroup

You’ll also need to mail enable any groups inside the groups, and you should be able to work this out based on the above commands.

Keep in mind you’ll probably want to hide all these groups from the address book so users can’t see them – in Exchange 2010 the GUI lets you mass select and change this option, but it’s also easy to do from PowerShell (but you’d need to 


Get-Group -resultsize unlimited | where {$_.name -like “mailbox“}| Set-DistributionGroup –HiddenFromAddressListsEnabled:$true

Note that if you use PowerShell to give a non mail-enabled Security Group access to a mailbox, it will appear in the Exchange admin center, but it won’t work. As far as EAC knows, it has no members because it’s not mail enabled. I found this out the hard way!

Conditional Access Makes MFA Migration Easier

Microsoft Azure’s Conditional Access is a really great way to get a company using Multi-Factor Authentication. The old argument of not wanting MFA to get in the way of logins constantly goes away with this solution, because it lets you set the rules and scenarios where MFA will and won’t trigger.

To be more accurate, the access controls that Conditional Access can use lets you use more than just MFA to log in (username/password/token style). You can set the rules so a trusted device negates the need for MFA.

This isn’t new anymore either. Here’s a video from Microsoft back in March 2017 talking about how all this works:

What this means is that someone with a username and password on a device that is either InTune enrolled, or set up for Azure AD Hybrid is trustworthy enough. Of course this is less secure than asking for MFA every time, but do you really need to do that when someone is using their work laptop?

Another condition to choose from is ‘Locations’. You can decide that MFA won’t kick in if the login is coming from inside your corporate network. You can also target different applications with different rules that stack – so maybe the payroll system will always ask for MFA, but a less sensitive one will only ask when not on a managed device.

Security wise, there’s also a ‘Sign-in Risk‘ option where each authentication attempt is evaluated and given a risk ranking, and access can be granted or blocked based on the results. Note that this one needs Azure AD Premium P2 which isn’t part of the Microsoft 365 E3 subscription – E5 or separate licensing is required.

Because Conditional Access works like a bunch of Outlook rules, you can slowly build up and adjust what kicks in when. It’s really easy to do, and there’s really no excuse (once you have licensing!) to stop you setting it up ready to demo to staff. 

Combine Conditional Access with Azure AD App Proxy where you can externalise any internal web based app, while forcing auth on it and you’ve got an easy way of enabling workers to do their jobs remotely, while being happy about the security around it – and NOT just poking a hole in a firewall, exposing your IIS box to the world.