Exchange Server Email Archiving

Many small and mid-sized companies in Germany still run their own Exchange Server. The mailbox is not an archive there: users delete emails, databases get cleaned up, and backups only cover points in time. German law requires you to keep business email in a form that cannot be altered or lost, which means an immutable copy of every relevant message.

Legal basis

• § 257 HGB (German Commercial Code) requires merchants to keep received business letters (Handelsbriefe) and copies of sent ones.
• § 147 AO (German Fiscal Code) extends this to tax-relevant documents. GoBD is the tax authority's rulebook for how electronic records must be kept: complete, unalterable and readable.
• The Federal Fiscal Court confirmed in order XI R 15/23 (30 April 2025) that emails can be business letters.

Retention periods: 6 years for business letters, 8 years for accounting vouchers including invoices, 10 years for books, annual financial statements and organisational documents. The 8 years apply since 1 January 2025 (BEG IV) to all documents whose old 10-year period had not ended by 31 December 2024 (Art. 97 § 19a EGAO). Banks, insurers and investment firms follow one year later. The period starts at the end of the calendar year. § 146 (2a) AO also allows you to keep electronic records in another EU member state.

The problem with Exchange alone

An on-premises Exchange mailbox can be emptied by the user, trimmed by a retention tag or lost with a database. None of that is logged in a way that proves completeness to an auditor. A separate archive fixes this, and with EasyMailArchive you do not have to operate another server to get one.

Step 1: Account and relay address

Sign up and open Admin > Integrations. Your relay address is shown there:

[email protected]

Step 2: Create the transport rule

In the Exchange Management Shell:

New-TransportRule -Name "EasyMailArchive" -BlindCopyTo [email protected] -Scope Global -Enabled $true

Or create a rule in the Exchange Admin Center under Mail flow > Rules that applies to all messages and sends a blind copy to the relay address.

Your Exchange must be allowed to deliver mail to external recipients. If outgoing mail goes through a smart host, the copy takes the same route. See the setup guide for details.

Step 3: Test

Send one email inbound, one outbound and one internal. All three appear in the search after a short time.

Step 4: Import existing mail over IMAP

1. Enable IMAP on the Exchange Server if it is not active yet.
2. In EasyMailArchive, go to Admin > Integrations > IMAP mailboxes, enter server, port and credentials for each mailbox and assign it to a user. See IMAP integrations.
3. EasyMailArchive reads all folders and skips emails that are already archived.

Step 5: Set retention

Rules apply per organisation, domain or mailbox, up to 10 years on Starter and Business. A typical setup is 10 years for everyone, with mailboxes that have no business use excluded. Retention runs in whole years to 31 December of the year. Mail is deleted only automatically when the period ends, and there is no delete function for single emails. Legal hold, available from Business, blocks deletion when you need it.

Compared with a local archive server

• No additional server, no updates, no storage planning
• AES-256 encryption with a separate key per customer, TLS in transit
• Hosted in the WITT AG data centre in Germany, with a separate database per customer
• Billed per license and month instead of a licence purchase: Starter 4 EUR, Business 9 EUR excl. VAT, from one user

For the auditor you export emails as original EML or as PDF with SHA-256 checksums. The audit log of all actions exports as CSV. A data processing agreement is available at /avv.

Read more

• GoBD email archiving
• Audit-proof email archiving
• Archiving Microsoft 365 email
• Archive an IMAP mailbox

See pricing or try it free for 30 days.

This article summarises the law in general terms and is not legal or tax advice.