A folder called “Archive” or “Old mail” can look much the same whether it lives in your mailbox or only inside one mail app. That difference matters when you replace a phone, reinstall an app or move to a computer: server-stored messages can usually be accessed from another device, while device-only messages may not come along automatically. Use the checks below to identify where a folder’s contents are held, preserve anything important and confirm your new setup can see the mail before you retire the old one.
The useful bits
- A folder’s name does not tell you where its messages are stored.
- Check the same mailbox from another device or webmail before assuming a folder is server-side.
- Keep the old setup until important messages are visible in the new one and any local-only mail is preserved.
Two places a folder can live
A server folder belongs to the mailbox itself. Mail apps connect to the mailbox and display those folders; when the account and folder are available, another device can usually access the same messages. An inbox, sent mail or a custom folder may be server-stored, but its name alone is not proof.
A device folder is held by a particular app or computer rather than in the mailbox. Some apps use labels such as “On my computer,” “Local folders” or “This device,” but wording varies. Messages in such a folder may remain available on that device without being uploaded to the mail server. A download or cached copy is different again: it may be stored locally for convenience even though the original message is still on the server.
Why the distinction shows up during a move
When you add an account to a replacement device, the app can retrieve mail that remains in the mailbox, subject to its sync and display settings. It cannot automatically retrieve a message that existed only in the old device’s local storage. Removing the old account, deleting the app or wiping the device before checking may make local-only mail difficult or impossible to recover.
Folder visibility can also differ without messages being missing. An app might hide a folder, show only recent mail, or have a different view of archived messages. Treat “I can’t see it in the new app” as a reason to investigate, not immediate proof that the mail is gone.
Check from a second view
Start with a message you can identify by sender, subject or approximate date. Sign in to the mailbox through its webmail service, if available, or add the account to another trusted device. Look for the folder and message there. If the message appears in the mailbox’s web view, that is useful evidence it is server-accessible; if it appears only in the old app, treat it as potentially local until you establish otherwise.
For BITTU Mail, account sign-in and account actions go through mail.bittuicloud.com. A compatible mail app can connect using IMAP at mx1.bittuicloud.com on port 993 with SSL/TLS. These connection details do not establish that a particular folder is server-stored; check the actual folder and messages. Never accept a certificate warning.
A migration check before you unplug the old setup
Use this short checklist while both devices are available:
- List the folders you care about and note any app labels suggesting local storage.
- Open a few important messages in each folder on the old device, then look for those same messages in webmail or another device.
- Add the account to the new device and allow its folders and messages to appear; check search and folder views as well as the inbox.
- If a message appears only on the old device, use the mail app’s documented export or copy-to-mailbox process, if available, and verify the copied message from another view.
- Keep the old device and its mail app unchanged until the important messages are confirmed elsewhere.
Example: You have a folder named “Project notes” on an old laptop. You find a key message there, then sign in to webmail and search for its subject. If it is not visible, do not assume the new phone will receive it. Check whether the laptop app identifies the folder as local, preserve or copy the message using that app’s available process, and then confirm it appears in webmail or on the new phone.
Confirm the result, not just the setup
After adding the account on the new device, check more than whether the account name appears. Open the folders that matter, search for the messages you noted, and open several messages to confirm their contents and attachments are accessible. If a folder is absent, check the app’s folder visibility or sync settings and compare again with webmail. Settings and labels differ between apps, so follow that app’s own instructions rather than assuming a particular menu or button.
Do not remove the old setup until you have verified the messages you need from the new device or another reliable location. If the old device is the only place a message appears and the app offers no clear way to preserve it, pause before deleting data and consult the app’s support documentation. The key test is simple: can you find and open the important mail somewhere other than the original device?
About this guide
Prepared with AI assistance for the BITTU Mail editorial library. Check important details against your original messages and current account settings. Product access depends on your role, plan and provisioning state. Provider interfaces and requirements can change.
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