Shared Mailbox Online Archiving Licensing in Office 365

Iron Contributor

Hello All,


I have a pretty interesting question ( i may already have an answer but need little clarity on this)


I have an Organization where i have more than 1000 Shared Mailboxes with Online Archive turned on.


All the shared mailboxes are running under capacity of 50 GB primary and are non affected with the recent change of Licensing and Provisioning of Shared Mailbox in Office 365 explained in this article -


Current situation is we have Online Archive already Turned ON for multiple shared Mailboxes which are also under control and the Highest we have reached is 90 GB for Online Archive of one of our Call Center Mailboxes (Service Desk).


my questions or queries on above situation are below - 


1. Do we need to apply license (archive add on) for our already existing Shared Mailboxes which are non licensed and have there Archive size more than 50 and less than 100. My concern is with Online Archive only as we have setup Retention Policies to auto archive all emails beyond 180 Days.


2. Now the next question is regarding online Archive of Shared Mailboxes which are approaching 100 GB Limit. Do i need to be worried or should i go for auto expand archive function for Tenant Level (Set-OrganizationConfig -AutoExpandingArchive $true) . The reason is simple , if online archive will go beyond 100 GB Automatically for Unlicensed Shared Mailboxes I'm happy to leave the Autoexpanding for tenant level to False only. However if License would be required to go beyond 100 Gb or will there be any problems once the Online Archive hits the threshold of 100 GB and stop archiving emails.


3. Next question is for future purpose. What if i turn on Auto Expanding Archive on Tenant Level. Does that impact in any which ways to my Unlicensed Shared Mailbox Archives. I know the limits for Archives is 170 GB Max for Mailbox Plans of 50 GB (Plan 1 License or Shared Mailbox) but in this case what is Microsoft's stand for threshold of 170 GB. I'm sure we wont hit that limit in any case of Unlicensed Shared Mailboxes and are happy to clear non-standard emails/data from Online Archive of those touching the threshold of 170 GB. But question again arises regarding Licensing for these Online Archives of Unlicensed Shared Mailboxes.


Happy for your feedback guys, and yes its a Rush request so please provide all your guidance and throw some light on this.









9 Replies

Shared mailboxes using the Online Archive feature need a Exchange Online Plan 1 license, regardless of the size. It's clearly stated in the documentation:


Now the real interesting question is whether auto-expanding archives are supported with Shared mailboxes. I've never tested it, but I cant see any technical reason why it will not work. Indeed, the documentation mentions that Shared mailboxes are supported:


In any case, you still need a license, regardless of the size of the Archive.

Vasil, thanks for your response.


Lets take a completely different scenario when we have 50 GB user Mailbox. (licensing with EO Plan 1 license as standalone or business essential/business premium subscription). If I enable archive on the same , it is initially 50 , then expands upto 100 automatically, but then to go further beyond upto is where i have 2 options - 

1. to open a case with MS and ask them to increase it from there end manually.

2. or i enable auto expanding which in turn increases my archive if it hits the threshold of 90% of total available usage and takes it upto 130 then 150 and finally 170.


My conflict of interest is Shared Mailboxes in my environment are alreay way below the limit of 50 (without license) as reinstated by Microsoft in may/june this year as part of provisioning correction and no where in that article it states about Online Archive limit revision, it only talks about Primary Mailbox usage and how to correct it if not already below 50 Gb if unlicensed).


 back to my point where in I stated i have shared mailboxes (where primary Mailbox ) is running below 50 gb , however the Online archive for them (some of them) is touching close to 90 gb's. now my questions are - 


1. Should i be already worried and apply Archive or Plan 2 License before it hits 100 GB.

2. Should i leave it as it is and have it be increased by Microsoft to further 130 and so on.


The reason i want to do so is not purchasing additional licenses is i already have my users with E3 licenses who are accessing these Shared Mailboxes (i dont have any user with Plan 1 , all are on E3 100 GB mailbox + unlimited archive)


There are few more questions regarding autoexpanding archive which are quite clear though my main concern still lies with Licensing for Unlicensed Shared Mailboxes who archive are above 50GB . Additionally, what if i turn on Auto Expanding, can i still control or set archivequotalimits / archivearninglimit to 50 GB so as to ensure my archives arent hitting threshold without license (if the license assignment is a mandate to use online archive in Shared Mailboxes)



Ankit Shukla

best response confirmed by ankit shukla (Iron Contributor)

No, the quota for E1 is 50GB, shared between the main mailbox and the archive. It does not get expanded, and if you mean the auto-expanding archives feature, this is only available with EO Plan 2 licenses. So in your examples, you will need EO plan 2 licenses regardless.

Hi Vasil,


I have just tested this for close to 4 tenants, where - 

1. I was able to provision online archive for a Shared Mailboxes without any license.

2. I was also able to increase Online archive (of course from help of Microsoft ) to 100 , then 130 and further 170 GB (even though the utilization wasn't that much for any of the archives.


So primary point over here is what microsoft commented in Provisioning of Shared Mailboxes to 50 GB only isnt valid for its archives. 

1. Archives can be provisioned without a license.

2. With Default size of 50 GB, and if you request Microsoft to increase it does go through , which means the threshold/quota at the Backend is only valid for Primary Mailbox and not archives.

3. Without license goes upto 170 GB.

4. to go beyond 170 , you need Plan 2 or Archive license , Plan 2 gives you Primary 100 + Unlimited archive. Archive only license gives you unlimited archive with no change in Primary Mailbox (50GB).



Please review above and test from your end, cause i have tested all these above and come up with the statements mentioned.



Ankit Shukla


There's nothing to test, the documentation is clear. The fact that Microsoft does not put restrictions in the code does not mean that you are OK to use this functionality without proper licensing. Well, you are free to use it without licenses, but if the Microsoft licensing guys come knocking on your door, things will get ugly.

My rule of thumb is : if in doubt a licence is required. Ultimately there are no free lunches. The fact Microsoft does not enforce licensing is often frustrating but there are often sound operational reasons why this is permitted. Again, if common sense says you need a licence you need one! Ensure compliance with your Global or Licensing Admistrator if you have permission to create / change / delete products and services within Microsoft 365 / Office 365.
Obviously that reply is to Ankit rather than Vasil!

@John Wynne  That's so True :) @Vasil Michev - thanks for your clarification on this.



It is now globally enforced to all Tenants worldwide on the Product when customer could provision an Online Archive and Expand it too without the need for a License :) 


Thanks again :)


1 best response

Accepted Solutions
best response confirmed by ankit shukla (Iron Contributor)

No, the quota for E1 is 50GB, shared between the main mailbox and the archive. It does not get expanded, and if you mean the auto-expanding archives feature, this is only available with EO Plan 2 licenses. So in your examples, you will need EO plan 2 licenses regardless.

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