u/PzSniper

Hey folks,

long-time lurker, first time posting something this specific. We’re not new to M365 migrations, but this split has a few constraints that make me want a sanity check from people who’ve actually done it recently.

The setup:

• Company splits into two. We’re taking 23 users to a brand new tenant with a new domain

• Old tenant = M365 Business Standard, licenses expire in ∼2 months but tenant will stay up for 3-4 months (old MSP keeps it alive).

• New tenant = M365 Business Premium, fresh.

• Goal: move mailboxes, OneDrives, SharePoint team sites (4-5, nothing huge), and Teams. Client would really like to avoid third-party tools this time.

Budget = strict,they’ll accept losing Teams channel history if needed.

We’ve done plenty of tenant-to-tenant with BitTitan/MigrationWiz before, so I know the “easy” way. This time I’m trying to stay 100% native.

What I’m planning:

1. Mailboxes (23)

Native cross-tenant mailbox move. I know the drill: buy the one-time Cross-Tenant User Data Migration license (can be on target only), create the multi-tenant Entra app with Mailbox.Migration, grant admin consent on both sides, set up the Org Relationship inbound/outbound, mail-enabled security group for scoping, then New-MigrationBatch -ExchangeRemoteMove.

My question: anyone done this recently on small Business tenants (not EA)? Docs say it works, but in real life, how’s the reliability? Any gotchas with delegates, shared calendars, or recurring meetings blowing up? Throttling is my biggest fear for a 23-user cut.

Plan B if we skip the license: convert everything to Shared Mailboxes before the Standards expire (50GB each), PST export via Compliance Search, then Network Upload PST import into the new tenant. It’s ugly but doable for 23. Would you just pay for the 23 migration licenses and be done with it?

2. Mail flow / coexistence

Client suggested "just put a transport rule on old Exchange to redirect to @newdomain.com". Yeah, that works on shared mailboxes even unlicensed, but if we do the native move, Exchange automatically converts the source mailbox to a MailUser with targetAddress, so the rule is redundant.

Real-world experience: do you trust the automatic MailUser forwarding, or do you keep an explicit rule for the first couple months? Worried about the old MSP pulling the plug early and us getting NDR loops.

3. SharePoint

This is where Microsoft annoys me. The official Cross-tenant SharePoint Migration is EA-only and billed per 100GB. We’re Business Premium, so no dice.

SPMT doesn’t do tenant-to-tenant directly. So my native options are:

a) PnP.PowerShell copy (loses versions, have to rebuild perms)

b) Leave old sites read-only and give users B2B guest access for 3 months, then archive

Anyone managed to get the cross-tenant SharePoint tool enabled without EA (via CSP maybe)? Or do you have a PnP script that doesn’t make you want to quit IT? I’m fine losing version history, I’m not fine rebuilding 200 unique permissions by hand.

4. Teams

I know UDM (the new Orchestrated User Data Migration, still in preview last I checked) moves mailboxes, OneDrive, 1:1 chats, group chats, and meetings. It explicitly does NOT move channel messages. Microsoft’s own doc: “This feature doesn't include migration of Teams content, channels or associated structure.”

So what do you actually do for channel history in a split? Tell the client “it’s gone, start fresh”? Or dump it with Graph (Get-MgTeamChannelMessage) and stick the JSON/HTML into a SharePoint library as a read-only archive? I don’t need the threads to be live, I just need them searchable for “what did we decide in February”.

If you’ve scripted this, was it worth the effort or just pain?

TL;DR:

23 users, company divestiture, old tenant dies in 3 months. Trying to go full-native: pay for cross-tenant mailbox licenses, PnP SharePoint manually, accept loss of Teams channel posts. Am I saving the client $1k in tools just to create 40 hours of manual work for myself?

Not looking for vendor pitches or links to MS Learn (I’ve read it, twice). Looking for “yeah we did this last quarter and here’s where it bit us.”

Appreciate any war stories.

Pz

Hey folks,

long-time lurker, first time posting something this specific. We’re not new to M365 migrations, but this split has a few constraints that make me want a sanity check from people who’ve actually done it recently.

The setup:

• Company splits into two. We’re taking 23 users to a brand new tenant with a new domain

• Old tenant = M365 Business Standard, licenses expire in ∼2 months but tenant will stay up for 3-4 months (old MSP keeps it alive).

• New tenant = M365 Business Premium, fresh.

• Goal: move mailboxes, OneDrives, SharePoint team sites (4-5, nothing huge), and Teams. Client would really like to avoid third-party tools this time.

Budget = strict,they’ll accept losing Teams channel history if needed.

We’ve done plenty of tenant-to-tenant with BitTitan/MigrationWiz before, so I know the “easy” way. This time I’m trying to stay 100% native.

What I’m planning:

1. Mailboxes (23)

Native cross-tenant mailbox move. I know the drill: buy the one-time Cross-Tenant User Data Migration license (can be on target only), create the multi-tenant Entra app with Mailbox.Migration, grant admin consent on both sides, set up the Org Relationship inbound/outbound, mail-enabled security group for scoping, then New-MigrationBatch -ExchangeRemoteMove.

My question: anyone done this recently on small Business tenants (not EA)? Docs say it works, but in real life, how’s the reliability? Any gotchas with delegates, shared calendars, or recurring meetings blowing up? Throttling is my biggest fear for a 23-user cut.

Plan B if we skip the license: convert everything to Shared Mailboxes before the Standards expire (50GB each), PST export via Compliance Search, then Network Upload PST import into the new tenant. It’s ugly but doable for 23. Would you just pay for the 23 migration licenses and be done with it?

2. Mail flow / coexistence

Client suggested "just put a transport rule on old Exchange to redirect to @newdomain.com". Yeah, that works on shared mailboxes even unlicensed, but if we do the native move, Exchange automatically converts the source mailbox to a MailUser with targetAddress, so the rule is redundant.

Real-world experience: do you trust the automatic MailUser forwarding, or do you keep an explicit rule for the first couple months? Worried about the old MSP pulling the plug early and us getting NDR loops.

3. SharePoint

This is where Microsoft annoys me. The official Cross-tenant SharePoint Migration is EA-only and billed per 100GB. We’re Business Premium, so no dice.

SPMT doesn’t do tenant-to-tenant directly. So my native options are:

a) PnP.PowerShell copy (loses versions, have to rebuild perms)

b) Leave old sites read-only and give users B2B guest access for 3 months, then archive

Anyone managed to get the cross-tenant SharePoint tool enabled without EA (via CSP maybe)? Or do you have a PnP script that doesn’t make you want to quit IT? I’m fine losing version history, I’m not fine rebuilding 200 unique permissions by hand.

4. Teams

I know UDM (the new Orchestrated User Data Migration, still in preview last I checked) moves mailboxes, OneDrive, 1:1 chats, group chats, and meetings. It explicitly does NOT move channel messages. Microsoft’s own doc: “This feature doesn't include migration of Teams content, channels or associated structure.”

So what do you actually do for channel history in a split? Tell the client “it’s gone, start fresh”? Or dump it with Graph (Get-MgTeamChannelMessage) and stick the JSON/HTML into a SharePoint library as a read-only archive? I don’t need the threads to be live, I just need them searchable for “what did we decide in February”.

If you’ve scripted this, was it worth the effort or just pain?

TL;DR:

23 users, company divestiture, old tenant dies in 3 months. Trying to go full-native: pay for cross-tenant mailbox licenses, PnP SharePoint manually, accept loss of Teams channel posts. Am I saving the client $1k in tools just to create 40 hours of manual work for myself?

Not looking for vendor pitches or links to MS Learn (I’ve read it, twice). Looking for “yeah we did this last quarter and here’s where it bit us.”

Appreciate any war stories.

Pz

Hi everyone,

I need to fetch/sync data from a column in a Microsoft List on SharePoint Site A into a Microsoft List on SharePoint Site B.

I know this can be done with Power Automate, but before building anything I’d like to understand what approach is recommended by people who have real-world experience with this scenario.

For example:

- One-time copy vs ongoing sync

- Power Automate (flows) vs other approaches (e.g. Graph API, scheduled jobs, etc.)

- Things to watch out for (permissions, performance, throttling, list size)

Has anyone dealt with this before, and what solution would you recommend?

Thanks!

Hi everyone,

I need to fetch/sync data from a column in a Microsoft List on SharePoint Site A into a Microsoft List on SharePoint Site B.

I know this can be done with Power Automate, but before building anything I’d like to understand what approach is recommended by people who have real-world experience with this scenario.

For example:

- One-time copy vs ongoing sync

- Power Automate (flows) vs other approaches (e.g. Graph API, scheduled jobs, etc.)

- Things to watch out for (permissions, performance, throttling, list size)

Has anyone dealt with this before, and what solution would you recommend?

Thanks!

Hi everyone,

I need to fetch/sync data from a column in a Microsoft List on SharePoint Site A into a Microsoft List on SharePoint Site B.

I know this can be done with Power Automate, but before building anything I’d like to understand what approach is recommended by people who have real-world experience with this scenario.

For example:

- One-time copy vs ongoing sync

- Power Automate (flows) vs other approaches (e.g. Graph API, scheduled jobs, etc.)

- Things to watch out for (permissions, performance, throttling, list size)

Has anyone dealt with this before, and what solution would you recommend?

Thanks!