Move from Microsoft 365 shared mailbox to Rinhelp
By Wilbert Liu, founder of Rinhelp · Facts checked · Markdown for AI agents
Email in a Microsoft 365 shared mailbox moves through Microsoft Graph, grouped into conversations by each message’s conversationId. Graph allows about 1,000 calls a minute per mailbox, but only four at once.
| Conversations | Time to read them from Microsoft 365 shared mailbox |
|---|---|
| 1,000 | about 1 minute |
| 10,000 | about 10 minutes |
Limit used: 1,000 requests a minute (per app per mailbox (10,000 calls in 10 minutes)), about 1 per conversation. Rinhelp takes up to 3,000 conversations a minute.
Free. Importing never emails your customers, never runs Rin and never counts toward a plan.
Needs a person. A Microsoft Entra Global Administrator approves Claude’s Microsoft 365 connector, or gives the AI agent’s app permission to read the shared mailbox. With delegated sign-in, the mailbox’s owner also has to share it with the account the AI agent uses.
Paste one prompt
Connect your AI agent to Rinhelp first, then paste the prompt for the app you use. It reads this page’s Markdown and follows Rinhelp’s steps.
Using Claude’s Microsoft 365 connector, follow https://rinhelp.com/migrate/microsoft-365.md and first tell me whether you can see our shared mailbox. The connector signs in as me and reads only what my account can, so if it can’t reach the mailbox, I’ll move the history with a coding agent.
Follow https://rinhelp.com/migrate/microsoft-365.md to move our shared mailbox into Rinhelp through Microsoft Graph, with an app that has application permissions or delegated access to it. List messages 1,000 a page, group them by conversationId, and fetch attachments with /$value. Keep to four calls at once on the mailbox.
Their words and ours
| In Microsoft 365 shared mailbox | In Rinhelp |
|---|---|
| Conversation (conversationId) | Conversation |
| Message | Message |
| Category | Tag |
What stays behind
- Mail flow rules
- Shared mailbox permissions
- Distribution lists
- Out-of-office settings
Microsoft 365 shared mailbox facts that shape the move
Outlook allows each app 10,000 calls in 10 minutes per mailbox, about 1,000 a minute. Source, checked .
Only four calls can run at the same time on one mailbox, and reading one mailbox doesn’t slow another. Source, checked .
Graph lists messages 10 at a time by default and up to 1,000 a page on request. Source, checked .
A shared mailbox can be read by an app with application permissions, or with delegated access to it. Source, checked .
Graph returns individual emails, not conversations, so each message’s conversationId is what groups them. Source, checked .
With delegated sign-in, a shared mailbox or folder its owner hasn’t shared with the signed-in user can’t be read. Source, checked .
Adding /$value to an attachment call fetches the file, and attachments that link to cloud files can’t be downloaded. Source, checked .
Graph’s mailbox export gives an opaque format with no standard-format option, and Microsoft points to the normal message calls instead. Source, checked .
Claude’s Microsoft 365 connector signs in as one person, reads only what that account can, and needs a Microsoft Entra Global Administrator to approve it. Source, checked .
Questions
Can we use Graph’s mailbox export instead?
No. Microsoft says that export is opaque with no standard format, and points to the normal message calls, which is what the AI agent uses.
Will attachments that link to cloud files come across?
No. Graph can’t download an attachment that is a link to a cloud file, so that file stays where it is. Ordinary attachments, up to 50 MB each, come across with their emails.
How long does a Microsoft 365 shared mailbox take?
Graph allows about 1,000 calls a minute per mailbox and a conversation takes about one, so roughly 10,000 conversations take around 10 minutes.