Outlook.com attachments to OneDrive: unanswered questions

There are unanswered questions about Microsoft’s ‘move’ of Outlook.com attachments to OneDrive storage.  Microsoft is being quite ‘opaque’ about the details of the change.

On 1 Feb 2023 the space used by attachments in an Outlook.com mailbox will be counted against the OneDrive space quota not the mailbox limit.  That’s a significant change which leads to many questions which Microsoft hasn’t answered.

See: Outlook.com will be using up your OneDrive quota
All about Outlook.com, OneDrive storage and Microsoft 365

This change won’t affect most people because they have plenty of space available in their OneDrive account.  Only folks already pushing their OneDrive quota limit need worry.

If you’re pushing the mailbox size limit (15GB or 50GB), the change could be a good thing by freeing up space.  Though that’s not necessarily the case, see below.

Microsoft is making this change of space allocation for their corporate benefit, not to help customers. We’re wary and looking at the details of this change.

Now and Then

Here’s our summary of the current situation and our understanding of the policy from 1 Feb 2023.

Now:

Outlook.com ‘free’ (non-Microsoft 365 plan) get

  • 15GB mailbox which includes
    • Email
    • Attachments
  • 5GB OneDrive

Outlook.com with linked Microsoft 365 plan get

  • 50GB mailbox which includes
    • Email
    • Attachments
  • 1TB OneDrive

1 Feb 2023 onwards.

 Outlook.com ‘free’ (non-Microsoft 365 plan) get

  • 15GB mailbox which includes
    • Email
  • 5GB OneDrive which now includes
    • Attachments from Outlook.com

  Outlook.com with linked Microsoft 365 plan get

  • 50GB mailbox which stores
    • Email
  • 1TB OneDrive which now includes
    • Attachments from Outlook.com

Which attachments?

Though its much less common, file attachments are possible to other Outlook items including Calendar and Contact items.

Will these attachments be affected by the change in quota distribution to OneDrive? In other words, when Microsoft speaks of ‘attachments’ do they mean attachments to any Outlook.com item in any folder, not just email?

We suspect the answer to this is, Yes.  All attachments will be ‘moved’, though Microsoft hasn’t clarified that point.

Email attachments can be in any folder including; Inbox, Sent Items, Junk Email and Deleted Items.

Where are the attachments stored?

Will there be a change in where attachments are stored on Microsoft’s system?  At present they are (presumably) stored in the same database as the emails (Exchange Server online).

Or perhaps there’s no real change in the way attachments are stored, just a change in how the space is accounted for?

Will Outlook.com attachments be available/visible in a customers OneDrive account (in a separate ‘Attachments’ folder)?  We suspect that will NOT happen but it’s a reasonable presumption given the change in the way attachment space is counted.

Double counting?

The presumption from Microsoft’s announcement is that the move of quota to OneDrive will mean a corresponding INcrease in mailbox space.

For example, a Microsoft 365 customer at the end of January 2023 has:

Outlook.com Mailbox

  • 27 GB used of 50GB
  • Including 5GB of attachments

OneDrive

  • 400GB used of 1TB (1000GB)

After the change of space allocation on 1 Feb 2023, the expectation is that the attachments space will be freed from the mailbox and taken from OneDrive like this:

Outlook.com Mailbox

  • 22 GB used of 50GB
    • The 5GB of attachments are NOT counted.

OneDrive

  • 405GB used of 1TB (1000GB)
    • The 5GB space used by attachments now included.

A careful reading of Microsoft’s announcement leaves some wriggle room for the company to add the space used to OneDrive while keeping the email attachment space still counted against the mailbox.

We hope that’s not going to happen but, over 20+ years, we’ve learnt to carefully read Microsoft announcements.

Outlook.com will be using up your OneDrive quota
All about Outlook.com, OneDrive storage and Microsoft 365
How to view and delete your Outlook.com attachments
All mailbox limits (& how to find yours) in Outlook.com and Microsoft hosting