8 months post-acquisition and we still have 200 people with active accounts in both tenants. Anyone actually finished one of these cleanly?

Posted by Prestigious-Fun-9680@reddit | sysadmin | View on Reddit | 10 comments

We acquired a smaller company last year. They were on Entra ID + on-prem AD. We're on Okta with Entra for M365. The plan was always to migrate everyone into our tenant by month 4. It's month 8.

Current state:

Acquired employees have their original accounts in the old Entra tenant still active because some line-of-business apps were never migrated and still auth against the old tenant. They also have guest accounts in our Entra for M365 access. And they have Okta accounts provisioned from our HR system for SSO into our SaaS stack. So each of these 200 people has three account objects across two IdPs and one of them is a guest account that keeps expiring and needs manual renewal every 60 days because nobody set up proper B2B policies.

Access reviews are a joke. When auditors ask "who has access to X" and X is in our tenant but the user's identity of record is still the old tenant, I genuinely don't know how to answer that cleanly. The user exists in both. Which one is authoritative? Depends on the app, apparently.

The part that's killing us right now is offboarding. One of the acquired employees resigned last week. We disabled their Okta account. Didn't touch the old tenant. They could still access old-tenant apps for another 4 days until someone noticed.

I know the answer is "finish the migration" but the business keeps deprioritizing the app migrations that are blocking it. So in the meantime, does anyone have a sane way to manage identity across two tenants for users in this limbo state? Specifically looking for how people handle the authoritative source of truth problem and offboarding across both systems simultaneously.