IMAP Path Prefix

What is it?

The IMAP Path Prefix (also called "IMAP Path" or "Namespace Prefix") tells your email client where to find your mailbox folders on the server. Some IMAP servers store folders inside a root folder like INBOX, while others use a flat structure where all folders (Inbox, Sent, Drafts, Trash, etc.) exist at the top level.

If this setting doesn't match how the server is configured, your client may show duplicate or nested folders. For example, you might see your Sent folder appear both at the top level and again nested under Inbox.

What should I set it to?

Leave the IMAP Path Prefix empty (blank).

Our servers use an empty namespace prefix. You should expect to see a folder layout like this:

• Inbox (top level)
  • Any folders you create will appear as subfolders under Inbox
• Sent (top level)
• Drafts (top level)
• Trash (top level)
• Junk (top level)
• Archive (top level)

The standard special folders (Sent, Drafts, Trash, Junk, Archive) exist at the top level alongside Inbox. Folders you create yourself will appear nested under Inbox.

Common issues

Apple Mail

Apple Mail defaults the IMAP Path Prefix to INBOX/. This causes folders to appear duplicated — once at the top level and again nested under Inbox. To fix this:

1. Open Mail > Settings (or Preferences)
2. Go to Accounts, select your MXroute account
3. Click Server Settings (or Advanced)
4. Clear the IMAP Path Prefix field so it is completely empty
5. Close Settings and restart Mail if needed

Thunderbird

Thunderbird typically auto-detects the correct settings via the IMAP NAMESPACE command, so no action is usually needed. If folders appear nested incorrectly:

1. Open Account Settings
2. Under Server Settings, find Advanced
3. Ensure the IMAP server directory field is empty

Outlook

Outlook generally auto-detects the namespace. If you see duplicated folders:

1. Go to File > Account Settings > Account Settings
2. Select your IMAP account and click Change
3. Click More Settings > Advanced
4. Clear the Root folder path field

Other clients

If your email client has a setting called any of the following, set it to empty/blank:

• IMAP Path Prefix
• IMAP Namespace
• IMAP server directory
• Root folder path
• Mailbox path prefix

Why does this happen?

IMAP servers define a "namespace" that describes their folder hierarchy. Our server configuration uses:

• Prefix: (empty) — folders are at the root level
• Separator: . (dot) — subfolder hierarchy uses dots (e.g., INBOX.subfolder)

On our servers, the standard special folders (Sent, Drafts, Trash, Junk, Archive) exist at the top level alongside INBOX, while user-created folders are stored as subfolders of INBOX using dot notation (e.g., INBOX.MyFolder).

When a client like Apple Mail assumes the prefix is INBOX/, it looks for folders inside INBOX and treats that as the root. This means it can't see the top-level special folders in their correct location, and may create duplicates or show an incorrect hierarchy.

Setting the prefix to empty tells your client to look at the root level, which matches how the server is configured. Your client will then correctly display the special folders at the top level and your personal folders nested under Inbox.