Google Workspace: cannot transfer file ownership to external accounts; client separation requires IMAP+DNS migration

Claim: Google Workspace forbids transferring file ownership to external accounts (cited as "user and company data" protection). When a client's email and Drive live in an agency's Google Workspace, separation requires:

1. Create a new Workspace under a temporary domain
2. Migrate mailboxes via IMAP with app passwords
3. Transfer Drive file ownership internally before account deletion
4. DNS cutover

Without the agency's cooperation at every step, the practical outcome is data loss.

Source: https://support.google.com/a/answer/1247799 (current Google Workspace admin documentation).

Confidence: Verified (primary Google documentation).

For Candid client onboarding: Workspace ownership is one of the most under-discussed ownership layers. If the client's email is on an agency Workspace, plan a multi-week separation BEFORE engagement ends. Item in Ownership Checklist: what an SMB must be able to walk away with at agency separation.