Migrating a 50 GB Gmail Workspace mailbox to Infomaniak doesn\'t happen with a single click. Between Google\'s IMAP quotas, Gmail\'s unique label logic, and Infomaniak\'s quota constraints, several obstacles can turn a simple migration into a nightmare. Here\'s the complete guide to anticipating problems and ensuring a successful migration.
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Google\'s Limitations: The First Obstacle
The first barrier to your migration doesn\'t come from Infomaniak, but from Google itself. Google imposes strict quotas on IMAP downloads.
The Google IMAP Quota
Google limits IMAP downloads to approximately 2.5 GB per day per account (2,500 MB/day). This limit is rarely clearly documented, but it is very real.
Quick Calculation
With 50 GB to migrate and a quota of 2.5 GB/day, expect at least 20 days of migration. In practice, plan for 3 to 4 weeks to be safe.
Blocking Risks
If you try to force through with too many parallel connections or excessive throughput, Google may:
- Temporarily block the account – IMAP access suspended for several hours
- Trigger security alerts – Suspicious connections detected
- Drastically throttle transfers – Aggressive throttling
Conclusion: a "one-shot" migration of a large Gmail mailbox is impossible. You need to plan incremental synchronizations over several days.
The Gmail Labels Trap
This is often the most misunderstood aspect of Gmail migrations. And it can triple the size of your mailbox.
Labels vs Folders: Two Incompatible Approaches
Gmail uses labels, not folders. A single email can have multiple labels (e.g., "Project X", "Client Y", "Important"). It\'s convenient for organizing emails without moving them.
But in IMAP (the protocol used for migration), labels become folders. And an email can only exist in one folder at a time... except that Gmail duplicates it into each folder corresponding to each label.
| In Gmail | After IMAP Migration |
|---|---|
| 1 email with 3 labels | 3 copies of the same email (1 per folder) |
| 50 GB reported | Potentially 100 to 150 GB actual |
| Flat structure with tags | Complex folder hierarchy |
Google\'s x3 Factor
Google officially acknowledges that the actual size of a mailbox can be up to 3 times larger than the size displayed in Gmail, due to this duplication caused by multiple labels.
How to Avoid Volume Explosion?
Before the migration, clean up your labels:
- Identify multi-labeled emails – These are the ones that will be duplicated
- Remove unnecessary labels – Obsolete archives, completed projects
- Merge redundant labels – "Clients" and "Client" for example
- Simplify your hierarchy – Fewer labels = less duplication
This preparatory work can easily cut the final migration volume in half.
On the Infomaniak Side: What You Need to Know About Quotas
Unlike Google, which imposes strict IMAP quotas, Infomaniak is much more flexible. But be careful, it all depends on your plan.
Quotas by Plan Type
| Plan Type | Mail Storage | Notes |
|---|---|---|
| Free plans (my kSuite, ik.me...) | 20 GB max | Mailbox stops receiving beyond this |
| kSuite Standard / Business / Enterprise | Unlimited | Paid plans with custom domain |
| Premium Mail Service | Unlimited | Professional plan with custom domain |
About the Displayed 20 GB
In the Infomaniak interface, you may sometimes see "20 GB" displayed even on a paid plan. This is an indicative limit. Infomaniak\'s documentation confirms that paid plans benefit from unlimited mail storage.
For a 50 GB migration (or even 100-150 GB after label duplication), make sure you\'re on a paid plan with a custom domain. Free plans won\'t be sufficient.
Other Technical Limits to Know
- Maximum email size – Approximately 201 MB (complete message including attachments)
- Attachments in webmail – Up to 25 MB directly, beyond that an automatic SwissTransfer link is generated (up to 3 GB), then direct SwissTransfer use (up to 50 GB)
- Emails per folder – No limit, but Infomaniak recommends not exceeding 4,000 to 5,000 emails per folder to avoid indexing slowdowns
Note for Large Mailboxes
If your Gmail inbox contains thousands of emails, consider creating subfolders to distribute the volume. This will prevent display and indexing slowdowns on Infomaniak.
Planning Your Migration: The Method That Works
A 50 GB migration can\'t be improvised. Here is the recommended strategy.
Phase 1: Preparation (Before the Migration)
- Audit labels – List all labels and identify redundancies
- Clean up the Gmail mailbox – Delete unnecessary archives, empty the trash
- Decide on scope – Migrate everything or only the last X years?
- Verify the Infomaniak plan – Paid plan = unlimited storage, free plan = 20 GB max
- Enable IMAP in Gmail – Settings > See all settings > Forwarding and POP/IMAP
Tip: Filter by Date
If you don\'t need the full history, only migrate emails from the last 2-3 years. This significantly reduces both volume and migration time.
Phase 2: Migration (Multiple Days)
Two main options:
Option A: Infomaniak\'s Migration Assistant
Infomaniak offers a built-in migration tool, intentionally limited to ~1 GB/day to respect Google quotas. It\'s the simplest but slowest solution.
- Advantage: No technical configuration needed
- Disadvantage: Minimum 50 days for 50 GB
Option B: imapsync (for technical users)
The imapsync tool provides more control but requires technical knowledge.
- Schedule daily syncs (cron job)
- Limit simultaneous connections (1-2 max)
- Enable logging to track errors
- Respect the 2.5 GB/day quota
Typical Workflow
- First full run – Launch the initial sync, which will take several days
- Incremental syncs – Run daily to catch up on new emails
- Monitoring – Watch logs and errors
- Final catch-up – Last sync just before DNS switchover
Phase 3: Verification (After the Migration)
Once the migration is complete, several checks are necessary:
| Folder | Verification |
|---|---|
| Inbox | All recent emails are present |
| Sent Items | Complete send history |
| Drafts | Important drafts preserved |
| Spam | Check that no legitimate email ended up there |
| Trash | Normally empty or to be emptied |
| Custom folders | Verify label mapping |
You can check the final mailbox size in the Infomaniak Manager for a clear view of the migrated volume.
Summary Checklist
Before the Migration
- ☐ Clean up Gmail labels (delete, merge)
- ☐ Empty trash and spam
- ☐ Decide on scope (everything or last X years)
- ☐ Verify the Infomaniak plan is paid (unlimited storage) and not free (20 GB max)
- ☐ Enable IMAP in Gmail settings
- ☐ Generate a Google app password if 2FA is enabled
During the Migration
- ☐ Respect the ~2.5 GB/day quota
- ☐ Limit simultaneous IMAP connections
- ☐ Monitor error logs
- ☐ Schedule daily incremental syncs
- ☐ Don\'t block the Google account (too many requests)
After the Migration
- ☐ Check sensitive folders (Inbox, Sent, Drafts)
- ☐ Verify final mailbox size
- ☐ Test sending and receiving
- ☐ Configure mail clients (Outlook, Thunderbird, mobile)
- ☐ Switch DNS records (MX)
Conclusion
Migrating a 50 GB Gmail Workspace mailbox to Infomaniak is technically feasible but requires preparation and patience. The main obstacles come from Google:
- The Google IMAP quota (2.5 GB/day) that forces a multi-week migration
- Gmail\'s label logic that can multiply volume by 2 or 3
On the Infomaniak side, with a paid plan (kSuite Standard/Business/Enterprise, Premium Mail Service), mail storage is unlimited. Your mailbox will be accommodated regardless of its size. Just remember not to exceed 4,000-5,000 emails per folder to maintain good performance.
By cleaning up your labels before migration and planning incremental synchronizations, you\'ll avoid unpleasant surprises. And if all this seems complex, don\'t hesitate to seek professional assistance.
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