30,000 contacts from a .PST file from export from New Outlook/Classic Outlook to import to Outlook 365

Question

30,000 contacts from a .PST file from export from New Outlook/Classic Outlook to import to Outlook 365

Sid Guel 5

I have over 30,000 contacts and they are missing from a .PST file that your support team put together for me from New Outlook/Classic Outlook. I need these contacts for importing into Outlook 365.

Sid Guel 5 Reputation points

2026-02-13T22:00:18.91+00:00

The .PST file does not have contacts. It is empty of contacts. I need assistance creating a new .PST or CSV file from new Outlook / Classic Outlook.
kagiyama yutaka 1,165 Reputation points

2026-02-13T22:05:44.35+00:00

when a PST comes back “missing” contacts, it’s almost always they pulled the mail store but not the real contacts store. i’d crack it open and check the hidden “Suggested Contacts” or the old Contacts sub‑folder , big sets like 30k get dumped there more often than you’d think.
Sid Guel 5 Reputation points

2026-02-13T22:09:30.1366667+00:00

Are these files on Microsoft servers?

"Suggested Contacts” or the "old Contacts" sub‑folders?

I don't see them on my laptop.
Sid Guel 5 Reputation points

2026-02-13T22:10:50.3566667+00:00

I'll check the .PST file again.
Sid Guel 5 Reputation points

2026-02-13T22:15:40.2133333+00:00

No. There are no sub folders called "Suggested Contacts” or the "old Contacts" on the .PST file. The contacts are just not there.
kagiyama yutaka 1,165 Reputation points

2026-02-13T22:21:00.6333333+00:00

Sorry if I’m off here, but pls check the original PC for any leftover OST/PST or old “Outlook Files”, and make sure another Outlook profile isn’t holding the contacts and support‑built PSTs often pull only the mail tree, so the contacts store never ends up in the file.
Sid Guel 5 Reputation points

2026-02-14T00:01:27.8433333+00:00

I've looked for both .PST and .OST files on my laptop. I'm certain that my contacts are on a Microsoft server somewhere. They are not local on my laptop.
Sid Guel 5 Reputation points

2026-02-17T16:46:24.07+00:00

I found what may be a contacts database file that's simply my email address. It's the only file that's large enough to hold my contacts and is updated every time I access my contact on New Outlook. I tried importing it as a .PST file but, it doesn't import and it has an error that states it can't import ,OST files. I looked at converters that take an .OST file and convert it to a .PST file but, they are expensive. I've looked for a free version but I have not found one yet. Any ideas?

2 answers

Your answer

Sid Guel 5 Reputation points

2026-02-13T22:00:18.91+00:00

The .PST file does not have contacts. It is empty of contacts. I need assistance creating a new .PST or CSV file from new Outlook / Classic Outlook.
kagiyama yutaka 1,165 Reputation points

2026-02-13T22:05:44.35+00:00

when a PST comes back “missing” contacts, it’s almost always they pulled the mail store but not the real contacts store. i’d crack it open and check the hidden “Suggested Contacts” or the old Contacts sub‑folder , big sets like 30k get dumped there more often than you’d think.
Sid Guel 5 Reputation points

2026-02-13T22:09:30.1366667+00:00

Are these files on Microsoft servers?

"Suggested Contacts” or the "old Contacts" sub‑folders?

I don't see them on my laptop.
Sid Guel 5 Reputation points

2026-02-13T22:10:50.3566667+00:00

I'll check the .PST file again.
Sid Guel 5 Reputation points

2026-02-13T22:15:40.2133333+00:00

No. There are no sub folders called "Suggested Contacts” or the "old Contacts" on the .PST file. The contacts are just not there.
kagiyama yutaka 1,165 Reputation points

2026-02-13T22:21:00.6333333+00:00

Sorry if I’m off here, but pls check the original PC for any leftover OST/PST or old “Outlook Files”, and make sure another Outlook profile isn’t holding the contacts and support‑built PSTs often pull only the mail tree, so the contacts store never ends up in the file.
Sid Guel 5 Reputation points

2026-02-14T00:01:27.8433333+00:00

I've looked for both .PST and .OST files on my laptop. I'm certain that my contacts are on a Microsoft server somewhere. They are not local on my laptop.
Sid Guel 5 Reputation points

2026-02-17T16:46:24.07+00:00

I found what may be a contacts database file that's simply my email address. It's the only file that's large enough to hold my contacts and is updated every time I access my contact on New Outlook. I tried importing it as a .PST file but, it doesn't import and it has an error that states it can't import ,OST files. I looked at converters that take an .OST file and convert it to a .PST file but, they are expensive. I've looked for a free version but I have not found one yet. Any ideas?

Answer 1

Sid Guel 5

When I go to outlook.live.com, there are only a few contacts there. I would guess maybe 30 contacts. It's the same email address [Moderator note: PII Removed]@sgbac.com but it has a different name SGBAC2.

This is not the account with the 30k contacts in it. I'm not sure where they are at, but they are certainly not local on my laptop.

Please help and thank you.

[Moderator note: PII Removed]@sgbac.com

[Moderator note: PII Removed]@charter.com

[Moderator note: PII Removed]@Mavsotech.com

Kal-D 4,700 Reputation points Microsoft External Staff Moderator

2026-03-02T22:00:35.04+00:00
Hi Sid Guel,

Thanks for confirming. If Outlook.live.com > People only shows ~30 contacts and the mailbox name looks different (SGBAC2), then you’re almost certainly signed into a different contact store/mailbox than the one showing the “30k” in New Outlook.

At this point, the key is to identify where New Outlook is actually pulling those 30,000 entries from (personal Contacts folder vs an organization Directory/GAL vs another connected account).

Next checks (please reply with the results)

Sign in via an InPrivate/Incognito window (to avoid cached logins), then go to Microsoft365.com > Outlook > People and sign in with @sgbac.com. Do you see the 30,000 contacts there, or still only a small set?

In New Outlook > People, are the “30k” listed under Your contacts / Contacts, or do they only appear when you search (which can indicate you’re seeing a Directory/organization list rather than personal contacts)?

In New Outlook > Settings > Accounts, do you see more than one account connected (for example, another Outlook.com/Gmail/Exchange account)? If yes, which account is selected in People when you view contacts?

Why this matters:

If the 30k are in the work/school mailbox People/Contacts, you should be able to export them using supported methods for that mailbox.

If the 30k are actually the Directory (GAL), they won’t export as personal contacts (and this may require your organization’s IT/admin policies).

If they belong to a different connected account, we’ll need to switch to that account’s People/Contacts and export from there.

Once you post back those 3 results, I can give the exact supported steps for New Outlook and Classic Outlook to export/import the correct contact set.

I'm looking forward to your reply.
Kal-D 4,700 Reputation points Microsoft External Staff Moderator

2026-03-05T18:32:52.9166667+00:00

Hi Sid Guel,

It's been a while and I am wondering if your situation got resolved.

If you need further clarification or assistance please don't hesitate to reach out

I'm looking forward to your reply,
Guel, Sid 0 Reputation points

2026-03-05T20:22:44.7+00:00

I need technical support assistance. If there's a duplicate email account at outlook.live.com but I can't find it. It's either SGBAC or SGBAC2

Answer 2

Hi Sid Guel,

Welcome to Microsoft Q&A.

From what you’re seeing (PST has no Contacts, and the file you found is an OST), it strongly suggests your contacts are stored in your online mailbox rather than in a local file. Also, OST files can’t be imported directly.

Quick Check

Open a browser and go to Outlook.live.com > People (or Outlook on the web > People if using a work/school account).
Do you see your 30,000 contacts there?

If yes: Your contacts are safely stored online. See the options below to sync or import them.
If no: Please let me know, and we'll troubleshoot further.

Option 1 (Recommended for New Outlook): Export/Import contacts using CSV via the web

If you're using New Outlook for Windows, the supported method to move contacts is CSV:

Go to Outlook on the web > People.
Select Manage contacts > Export contacts > All contacts.
Import the CSV using the steps here: Import or export contacts in Outlook using a CSV file.

Tip for large imports: For best results with 30,000 contacts, ensure your CSV file uses UTF-8 encoding. This prevents issues with special characters and ensures all contacts import correctly.

Option 2 (Classic Outlook): CSV import with field mapping (important for large lists)

If using Classic Outlook, you can import a CSV with field mapping to ensure columns align correctly:

Export contacts to CSV from Outlook on the web (as above).
In Classic Outlook, go to File > Open & Export > Import/Export.
Choose Import from another program or file > Comma Separated Values.
In the wizard, click Map Custom Fields to match your CSV columns to Outlook fields.

For reference: Import contacts from an Excel spreadsheet to classic Outlook.

Option 3: Access Online Contacts Directly (Classic Outlook)

If you can open both the old account and the new account in Classic Outlook, you can often copy contacts directly between the two Contacts folders (People view), which avoids CSV formatting issues for very large contact sets.

Quick check so I can point you to the exact best path:

Do your 30,000 contacts show in Outlook.com > People in a browser?
Is the target “Outlook 365” a personal Outlook.com/Microsoft account or a work/school Microsoft 365 account?

Note: If it’s work/school, I can still provide general client-side steps, but anything tenant/admin-side would need your organization’s IT admin.

Please let me know if this proves useful to you, or if you would like further assistance.

I'm looking forward to your reply.

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30,000 contacts from a .PST file from export from New Outlook/Classic Outlook to import to Outlook 365

2 answers

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