Help GuideLog in to the Mimecast Administration Console → Archive → Saved Searches → right-click a Saved Search → Export Search → choose EML or PST format → Save. Then go to Governance & Compliance → Exports & Updates and download each batch when status shows Complete. Important: You cannot export directly from Archive Search — you must use Saved Searches. Need to convert the export to PST or MBOX? Use Univik Mimecast Archive Converter.
📋 On This Page
Log in to the Mimecast Administration Console
Access the admin console using your administrator credentials
Open your browser and go to the Mimecast Administration Console at https://login.mimecast.com. Log in using your Super Administrator, Full Administrator or Discovery Officer account credentials.
Create a New Saved Search
Define the search criteria for the messages you want to export
In the Saved Searches section, click New Search (or the folder icon to create a new search folder first). Define your search criteria: date range, sender address, recipient address, subject keywords, and any other filters needed to scope your export precisely.
Save and Run the Search
Save your search criteria so the export option becomes available
Click Save and Exit to save your search. Mimecast will run the search automatically and the results will appear inside your Saved Search folder. You can click the search to preview message counts and verify the scope before exporting.
Right-Click the Saved Search and Select Export Search
Initiate the export and choose your output format
Right-click on the Saved Search name in the tree to open the context menu. Select Export Search from the menu. A dialog box will open where you configure the export.
After clicking Export Search, the export configuration dialog opens. Fill in the export name and select your format:
Download Export Batches from Governance & Compliance
Monitor export status and download each batch as it completes
After clicking Save, go to Governance & Compliance → Exports & Updates in the top navigation. Your export will appear in the list with a status indicator. Large exports are automatically split into 500MB batches — each batch appears as a separate row and must be downloaded individually.
| Export Name | Format | Messages | Batch | Status | Action |
|---|---|---|---|---|---|
| All Mail Export Jan–Mar 2026 | EML | 28,491 | 1 of 6 | Complete | Download |
| All Mail Export Jan–Mar 2026 | EML | 28,491 | 2 of 6 | Complete | Download |
| All Mail Export Jan–Mar 2026 | EML | 28,491 | 3 of 6 | Processing | — |
| All Mail Export Jan–Mar 2026 | EML | 28,491 | 4 of 6 | Pending | — |
What is Inside the Mimecast Export?
Mimecast delivers exports as 500MB ZIP batches. Each ZIP contains individual EML files — one per archived message. Unzip any batch to see the EML files inside. The full export for a large archive may span many batches that together form your complete archive.
| Property | EML Export | PST Export |
|---|---|---|
| Container | ZIP batches (~500MB each) | Single PST file |
| Email format | EML (RFC 5322 / SJF) | Microsoft Outlook PST |
| Opens in Outlook? | No — needs conversion | Yes — import directly |
| Headers included | Full header chain including X-Mimecast headers | Standard headers |
| BCC recipients | Included if option enabled at export | Included if option enabled |
| Attachments | Encoded inline as MIME parts | Embedded in PST |
Convert Mimecast Export to PST, MBOX or PDF
Mimecast EML ZIP batches cannot be opened in Outlook directly. To use your archived emails you need to convert them. Univik Mimecast Archive Converter loads all ZIP batches at once and merges them into a single output file:
- Outlook / Microsoft 365 — Convert EML ZIP batches to PST
- Thunderbird / Gmail — Convert to MBOX format
- Legal / Compliance — Convert to PDF with X-Mimecast header preservation
- Long-term archiving — Convert to MSG, HTML or MHTML
Load all Mimecast ZIP batches at once and convert to PST, MBOX, PDF and 10+ formats. Merges batches automatically. Preserves X-Mimecast headers. 100% offline.
Frequently Asked Questions
.eml files natively. You need to convert the EML ZIP batches to PST format first. Univik Mimecast Archive Converter loads all ZIP batches in one session, merges them and converts to a fully importable PST file for any Outlook version or Microsoft 365.X-Mimecast-Originator, X-Mimecast-Spam-Score, X-Mimecast-Spam-Diagnosed, SPF/DKIM/DMARC results and all X-headers written by Mimecast's filtering engine. These are critical for legal admissibility. PST exports retain standard headers but may not preserve all Mimecast-specific X-headers.
Troubleshooting Common Issues
This means your account does not have Discovery Officer, Full Administrator or Super Administrator permissions. Contact your Mimecast administrator and ask them to grant your account one of these roles. Alternatively, have an administrator run the export on your behalf.
Large exports can take several hours to process, especially if your organisation has other exports running (max 5 concurrent). Check the Exports & Updates page for how many other exports are active. If no other exports are running and yours has been pending for more than 24 hours, raise a support ticket with Mimecast Support.
If you clicked "Generate Next Export Block" while a batch was still downloading, Mimecast deleted it from its server. You will need to re-run the export from scratch — go back to Saved Searches, right-click the same search and select Export Search again. Make sure each batch download completes fully (check file size matches) before clicking to generate the next batch.
Check that your Saved Search criteria match the date range and accounts you intended. Mimecast only archives messages that passed through its filtering — messages from before Mimecast was configured will not be present. Also verify that you have not inadvertently filtered by sender or recipient. If messages were placed on Legal Hold they may require separate export from the Case Management section.
EML files extracted from Mimecast ZIP batches cannot be opened in Outlook. Use Univik Mimecast Archive Converter to load all ZIP batches and convert to PST, MBOX or other formats. The converter handles all Mimecast EML naming conventions and merges multiple batches automatically without any manual extraction.
Load all Mimecast ZIP batches at once — no manual extraction. Convert to PST, MBOX, PDF and 10+ formats. Merges batches automatically. 100% offline.
About This Guide
This guide is written and maintained by the Univik team, developers of file conversion and digital forensics tools since 2013. We verify each guide against the latest version of each email archive platform. Last verified: March 2026 with Mimecast Administration Console.
Related guides: Export from Mail Assure | Export from Google Vault | Export from Barracuda | Export from Proofpoint
