Every year someone formats a PC and then discovers their entire email history lived in one file on that disk. Do the backup before the migration, while it takes ten calm minutes instead of being impossible.
✍️ Technical Anshu📧 Microsoft Outlook⏱️ 15 minute backup
🎥 Watch the full process in the video - Outlook setup, profiles and every error fix, step by step
For POP accounts, the PST file is the mailbox - mail, contacts, calendar and tasks, often going back years, in a single file. IMAP users have a server copy, but local folders and archives are PST-only too. This guide covers the two correct backup methods, how to verify the backup actually opens, and how to bring it into Outlook on the new machine.
File Explorer - Outlook Files_ □ X
mailbox.pst18.4 GB - modified today
archive-2021.pst9.1 GB
Backup copy on external driveSize matches - verified
A healthy backup looks boring: same file names, same sizes, on a different drive. If the copy is much smaller, it did not finish
1
Know Exactly Which Files to Back Up
Open File > Account Settings > Account Settings > Data Files and note every file listed, with paths
Live POP PSTs usually sit in C:\Users\YourName\Documents\Outlook Files
Archive PSTs may live anywhere you created them - the Data Files list is the truth, not your memory
Do not back up OST files for this purpose - they are rebuildable caches, and a copied OST is not an importable mailbox
2
Method One - Copy the PST with Outlook Closed
The simplest and most faithful backup:
Close Outlook and confirm in Task Manager that OUTLOOK.EXE has fully exited - copying a PST while Outlook holds it open can produce a corrupt copy
Copy each PST to an external drive or another machine
Compare file sizes: the copy must match the original exactly. A smaller copy means the transfer was interrupted
3
Method Two - Export Through Outlook
File > Open & Export > Import/Export > Export to a file > Outlook Data File (.pst)
Select the top mailbox, tick Include subfolders, and save to your backup drive
Leave the password field blank unless you truly need it - a forgotten PST password on your own backup is a self-made lockout
Export is ideal when you want only part of the mailbox (one account, one year)
4
Verify the Backup Before You Trust It
An untested backup is a hope, not a backup:
On the same PC, use File > Open & Export > Open Outlook Data File and open the copy
Browse a few folders, open an old email with an attachment, check contacts
Close the copy from Outlook (right-click its name > Close) afterwards
Only after this test should the old PC be formatted, sold or handed back
5
Bring the PST into the New PC
Install Office and create the profile on the new PC first, adding the email account normally
For a POP mailbox: File > Account Settings > Data Files > Add, select your backed-up PST, and set it as Default, then restart Outlook
For archives: simply open them with Open Outlook Data File whenever needed - do not merge archives into the live mailbox
Keep the backup copy untouched until the new setup has run happily for a few weeks
🔴 The classic mistake: copying the PST while Outlook is still open in the tray, getting a quietly truncated file, and discovering it after the old PC is gone. Close Outlook, verify the size, open the copy once - three habits that make this boring instead of tragic.
🎥 Watch the Complete Process in the Video
Account setup, IMAP and POP settings, profiles, ScanPST - the full Outlook guide with live demo, step by step.
Can I just copy the OST file to the new PC instead
No. An OST is a cache tied to its profile and account - it cannot be imported as a mailbox on a new PC. IMAP and Exchange mail resyncs from the server; anything local-only should be exported to a PST first.
Should I set a password on my backup PST
Only if the drive itself is not protected and the mail is sensitive - and only if you will remember it. A forgotten PST password locks you out of your own backup with no official recovery route.
How often should I back up my PST
For a POP mailbox that matters, weekly to an external drive is a sane rhythm, plus one copy before any migration, format or laptop handover. The backup takes minutes; rebuilding a lost decade of mail takes forever, because it is impossible.
This guide is based on the Outlook Full Setup and Error Fix video by Technical Anshu • Stuck on any step, ask in the video comments and the community will help you 🙏