An old mail archive can look intact while important pieces are missing: a folder may not have copied, a message may open without its attachment, or the new app may show only part of the collection. Before treating a new device or account as your main place to work, make the archive’s contents visible, preserve a copy you do not alter, and test a small but meaningful selection. This approach does not depend on a particular mail app. It helps you spot gaps early and gives you a clear fallback if the transfer needs to be repeated.
The useful bits
- Record folders, date ranges, and special message types before moving anything.
- Keep an untouched archive copy separate from the copy you import or sync.
- Check messages and attachments on the new setup before relying on it.
Map what you actually have
Start on the device or in the app where the archive currently opens correctly. Write down the account or archive name, the folders you care about, and the oldest and newest dates visible in each. Note special groups that may be easy to overlook, such as sent mail, drafts, archived messages, or folders you created yourself. Include an approximate message count only if the app displays one; do not assume a count is complete just because it appears on screen.
Choose a few identifiable messages to use as reference points: one near the start of the archive, one near the end, and examples from important folders. Record sender, subject, date, and folder. For messages with attachments, note each filename and, if shown, its file type. This inventory is a comparison aid, not a replacement for the mail.
Protect an original before changing the setup
Use the current mail app’s supported export, archive, or backup process to make a separate copy, if one is available. Save it somewhere distinct from the working archive and label it clearly as the original backup, with the date you made it. Keep the source account or archive in place while you prepare the new setup. Do not use a move, delete, or cleanup operation as a shortcut to transferring mail.
An export file is useful only if you can still locate it and the app can read it. Keep a note of the file name and storage location, and avoid editing or re-saving the backup through another app. If the old app offers no suitable export, ask its documentation or support how it preserves mail before proceeding. Do not assume that seeing old messages on a second device proves you have an independent backup.
Move a working copy, not your safety net
Follow the import or migration instructions for the specific mail app and archive format. If the app offers a choice between copying and moving, choose copying for the first pass. Preserve folder organization where possible, but prioritize retaining the messages and attachments; you can tidy names later, after checking the transfer.
If you are configuring BITTU Mail in a separate mail app, the published IMAP settings are mx1.bittuicloud.com on port 993 with SSL/TLS. For outgoing mail, use the same host on port 465 with SSL/TLS or port 587 with STARTTLS, authentication, and the full mailbox address as the username. Never use port 25 for a mail app, and do not accept certificate warnings. These connection settings do not themselves explain how to import an old archive; use the app’s instructions for that step.
Check a representative sample
On the new device or in the new app, compare the reference messages with your inventory. Open each one, confirm its sender, subject, date, and folder, and check that the body is readable. Search for a distinctive subject as well as browsing the folder. If a message appears in search but not where expected, investigate before concluding the folder structure transferred correctly.
For attachment messages, open or download each file and confirm that it has the expected name and can be read by an appropriate app. A visible paperclip or filename alone is not proof that the file opens. Do not open an attachment that you consider unsafe; verify its presence and details without taking that risk. Check more than one folder and date range, including any especially important correspondence.
Reference sample Folder: Projects Message: [sender@example.com] — [subject] — [date] Attachment: [filename] — [file type] New setup: message opens; details match; attachment opens
Use a small checklist before relying on it
Compare the folder list with your inventory, then check the reference messages and attachment files. Confirm that the earliest and latest samples are present, not just recent mail. If the app shows counts, compare them cautiously: counts can differ because of filters, folders, or how the app displays conversations. A mismatch is a reason to investigate, not by itself proof of lost mail.
Keep the untouched backup and old source until you have resolved missing folders, unreadable messages, or absent attachments. If a transfer failed, stop and consult the relevant app’s import instructions rather than repeating a move on the only copy. When the checks pass, retain the backup as a fallback and make future archive copies using a repeatable process. This verifies a sample, not every message; for a large or critical archive, check additional high-value folders before depending on it.
- Folder list and date range compared
- Older and newer reference messages open
- Important attachment filenames and files checked
- Untouched backup still available
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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