Migrate Rackspace Email to Gmail: IMAP Cutover Guide

Rackspace's email products have lost ground steadily over the last decade. After the 2022 Hosted Exchange security incident and the pricing shifts that followed, plenty of small businesses and IT teams found themselves with a Rackspace mailbox they want to leave but a custom domain they want to keep. Gmail — either a free account for personal mail or Google Workspace for the domain — is one of the common destinations. This guide walks the IMAP transfer, the differences between Rackspace Email and Rackspace Hosted Exchange, and the MX cutover sequence that doesn't drop inbound mail.

Identify which Rackspace mail product you have#

Rackspace sells two email products with the same brand. The source IMAP endpoint and a few of the quirks differ:

Rackspace Email is Rackspace's homegrown mail platform. Source IMAP:

• Server: secure.emailsrvr.com
• Port: 993
• SSL: yes

Rackspace Hosted Exchange is Microsoft Exchange Server with Rackspace's hosting and admin layer. Source IMAP:

• Server: mex##.emailsrvr.com where ## is your cluster number (visible in the admin console)
• Port: 993
• SSL: yes

Check the Rackspace Cloud Office control panel to confirm which product covers your domain. Some customers have both — a small Exchange tenant plus a few Rackspace Email mailboxes. Each migrates separately.

Pick your Gmail destination shape#

"Gmail" can mean two different things:

• A free @gmail.com consumer account
• A Google Workspace mailbox on your custom domain (formerly G Suite)

Choose free Gmail when:

• You're migrating a single personal account
• Your custom domain is going away or you don't mind forwarding only
• You have 15GB or less of mail history

Choose Google Workspace when:

• You need to keep @yourbusiness.com hosted at Google
• You have multiple users on the same domain
• You want shared drives, Workspace admin tooling, and per-user policies

This guide covers the IMAP transfer mechanics, which are similar for both destinations. If the destination is Google Workspace, our Rackspace to Google Workspace guide covers the additional tenant setup steps.

Pre-flight checklist#

Before launching:

• Confirmed Rackspace product (Email vs Hosted Exchange)
• Current Rackspace mailbox password
• Active Gmail destination account
• For 2FA-enabled Gmail accounts: a Google app password
• Estimate of Rackspace mailbox size (Cloud Office shows this in the admin panel)
• Gmail destination quota with at least 20 percent headroom over the source size

Step 1: Confirm IMAP is on at the destination#

For a free Gmail account:

1. Sign in to mail.google.com
2. Open Settings (gear icon), See all settings
3. Forwarding and POP/IMAP tab
4. Confirm IMAP access is set to "Enable IMAP"
5. Save changes

For Google Workspace:

1. Workspace admin signs into admin.google.com
2. Apps, Google Workspace, Gmail, End User Access
3. Confirm IMAP is enabled for the destination user's organisational unit

Step 2: Generate a Google app password#

If the destination Gmail account has 2-Step Verification on (which it should), generate an app password.

1. Sign in to myaccount.google.com
2. Security, 2-Step Verification (must be enabled first)
3. App passwords (sometimes hidden until 2SV is fully enrolled)
4. Generate a new app password named Mailbox Taxi
5. Copy the 16-character password (Google shows it once)

If you don't see App passwords as an option, your Google admin (for Workspace accounts) may have disabled it. Re-enable it in the admin console under Security, Less secure apps, or for newer admin consoles, Security, Authentication. Background on app-specific passwords across providers lives in our app password reference.

Step 3: Configure the source#

For Rackspace Email:

• Server: secure.emailsrvr.com
• Port: 993, SSL on
• Username: full email address
• Password: Rackspace mailbox password

For Rackspace Hosted Exchange:

• Server: from your Rackspace admin console (e.g. mex01.emailsrvr.com)
• Port: 993, SSL on
• Username: full email address
• Password: Exchange mailbox password

Test the source connection in a desktop mail client first. If it accepts the credentials and lists folders, you're ready.

Step 4: Folder mapping#

Rackspace Email's system folder names:

• INBOX
• Sent
• Drafts
• Trash
• Spam

Gmail's quirks:

• Gmail uses labels rather than folders, but exposes them as IMAP folders
• The [Gmail] namespace contains system folders: [Gmail]/Sent Mail, [Gmail]/Drafts, [Gmail]/Trash, [Gmail]/Spam, [Gmail]/All Mail
• Gmail does NOT have a literal Inbox folder — mail goes to INBOX which is the all-mail conversation view filtered by the inbox label

Map explicitly:

• Rackspace INBOX → Gmail INBOX
• Rackspace Sent → Gmail [Gmail]/Sent Mail
• Rackspace Drafts → Gmail [Gmail]/Drafts
• Rackspace Trash → Gmail [Gmail]/Trash
• Rackspace Spam → Gmail [Gmail]/Spam

User folders carry over as labels in Gmail.

Step 5: Pilot one folder#

Pick the Sent folder or a stable user folder of 200 to 500 messages. Avoid the Inbox because it churns during the migration.

Verify on completion:

• Final count matches between Rackspace and Gmail
• Messages sort by date correctly in Gmail (confirms INTERNALDATE preserved)
• Read/unread flags carry over
• Three random messages open with attachments intact from the Gmail web UI
• No Folder UTF-7 conversion error in the run log

Step 6: Run the full transfer#

Concurrency for this pair:

• Rackspace source: 3 to 4 connections (Rackspace handles parallel fetch well)
• Gmail destination: 2 connections (Gmail throttles IMAP append above 2 to 3 per user)

Throughput: 500MB to 1.5GB per hour. Faster than iCloud-source migrations because Rackspace doesn't aggressively throttle.

• 5GB mailbox: 1 to 3 hours
• 25GB mailbox: 6 to 12 hours, plan overnight
• 50GB mailbox: multi-session, plan across two days

Gmail-side throttling kicks in if you hammer the destination. You'll see OAuth2 token expired (even though we're using app passwords — Gmail occasionally uses this error misleadingly) or simply slow responses. Mailbox Taxi backs off automatically when it sees the pattern.

Step 7: Verify#

When the run finishes:

1. Folder/label counts side by side
2. Spot-check messages from 2018, 2021, 2024 — open them, confirm content and attachments
3. Test sending and receiving on Gmail
4. Confirm folder structure looks right in Gmail web UI (labels appear in the left sidebar)

If counts are off by more than a few per folder, run a delta sync.

Step 8: Cut over MX or set up forwarding#

For free Gmail destinations:

Forward Rackspace to Gmail.

1. Sign into the Rackspace email admin
2. Open the user's mailbox settings, Forwarding
3. Forward all mail to your Gmail address
4. Save

Keep this running for 60 to 90 days while you update your address with senders.

For Google Workspace destinations:

You can move MX records to Google. The sequence:

1. Confirm the Workspace tenant verifies your custom domain
2. Add the MX records Google provides (5 records, priority 1, 5, 5, 10, 10)
3. Lower TTL on the existing Rackspace MX records to 300 seconds 24 hours before the change
4. Replace Rackspace MX records with Google's
5. Mail arriving during the propagation window (5 to 60 minutes typically) lands at both providers — that's expected
6. After 48 hours, all mail flows to Google

Common failures#

AUTHENTICATIONFAILED on Rackspace source: most often a password with special characters. Reset to one without backslashes or quotes.

AUTHENTICATIONFAILED on Gmail destination: 2SV is on and you tried to use the account password. Generate an app password.

OAuth2 token expired on Gmail (even with app password): Gmail's misleading error for general throttle. Drop destination concurrency to 1 and retry.

Too many simultaneous connections on Gmail: you exceeded 15 IMAP connections from a single user. Drop to 2 and continue.

STARTTLS handshake failed on Rackspace: corporate VPN with TLS inspection. Run from off-network.

After the migration#

• Update senders to the new address
• Run an auto-reply on the Rackspace mailbox for 30 to 60 days
• Don't shut down Rackspace immediately — keep forwarding for 90 days to catch infrequent contacts
• Export Rackspace contacts and calendar to CSV/ICS before final shutdown
• Revoke the Google app password from myaccount.google.com

If Outlook is the right destination instead, our Rackspace to Outlook guide covers that route. For Office 365, see Rackspace to Office 365. The complete email migration guide covers the broader DNS, SPF, DKIM, and DMARC sequence beyond just the mailbox.