What to do with old PST files before you delete or import them

What should you do with old PST files?

Inventory them before you delete or import anything. A PST is an Outlook data file, and a forgotten one on a laptop or file share can hold years of email that never reached Microsoft 365. Record where each file sits, how big it is, who it belongs to and when it was last touched, then let the business owner decide: import, archive or delete.

Most "PST eradication" projects skip the decision step and go straight to import or deletion. For a client with 50+ full-time employees at peak (contractors excluded), that can erase the longest email history the company still has. The inventory below moves no content and opens no mailbox.

Why PST files are worth a second look before cleanup

Many companies saved Outlook mail to local data files in the past, or exported mailboxes to PST during migrations and when staff left. The result is a scatter of archives on laptops, network shares, backup volumes and external drives.

Two things make them more than clutter:

• Compliance exposure. An unmanaged PST sits outside whatever retention and search rules the tenant applies to live mailboxes. Your client's counsel should know the files exist before anyone deletes or imports them.
• Business history. Years of customer threads, approvals and escalations may exist nowhere else. If the company later explores licensing its operational records, that history is part of the picture. The former employee mailbox guide covers the same question for departed users.

How do you build a metadata-only PST inventory?

Collect facts about the files, never their contents. The steps below work with a file-system scan or the endpoint tool you already run.

1. Agree scope in writing. Get the client's sign-off on a scan of named shares and managed laptops, limited to file name, path, size and dates.
2. Scan for the .pst extension on file servers, user profile folders, backup volumes and attached drives. Also look for .ost orphans and archive folders named after years.
3. Record the metadata in a sheet: path, size, created and modified dates, the owning account from file permissions, and the machine or share.
4. Match files to people. Mark each owner as active, departed or unknown. Departed and unknown are the rows that matter most.
5. Check whether the mail is already elsewhere. Compare date ranges against what the live mailbox or archive covers, using the user's own folder dates, not message content.
6. Hand the sheet to the owner with one question per cluster: keep, import, archive or delete, and who decides.

Do not open files, preview messages or copy a PST off the client's systems. A partner who touches the content has stepped outside what a referral requires.

What does the inventory sheet look like?

Which option fits which PST cluster?

Import is a sound choice when staff need the mail. It is a poor first move when the question is still open, because moving mail into live mailboxes can scatter a clean historical archive across many accounts.

When does a PST pile become a SourceX conversation?

Raise it when the inventory shows depth, not just volume. Use this quick screen:

• The company has 50+ full-time employees at peak (contractors excluded).
• The oldest files go back several years across many users.
• Other systems (CRM, tickets, finance) also hold long histories, as strong candidates usually run 10-15+ systems.
• The company created the mail and has the right to license it, which usually means checking client confidentiality terms and employee notices.
• An owner, CEO, CFO or authorized representative can make a decision.

If most boxes tick, tell the owner that a data licensing assessment may be worth a conversation before cleanup. Your role is to surface the question. SourceX qualifies the company, runs the data inventory with its sponsor, agrees price and terms, and manages buyer review. Redaction rules for personal or client information are agreed with the company before any work begins.

What to say to the client owner

Pair it with the broader MSP revenue guide if you are deciding how this fits your service mix.

What the partner reward covers

Partners earn 25% of the eligible platform fees SourceX actually collects from the referred company's licensing deals, capped at $100,000 per referred company. The reward is paid only after the buyer pays and SourceX receives its fee; an introduction, meeting or signed agreement alone does not trigger payment, and no reward is guaranteed. A licensed professional should check their own rules on referral fees and disclosure, and MSPs should tell clients about the relationship when making the introduction.

When not to bother

• The files belong mostly to the client's customers, for example an outsourcer holding client mail, and those customers have not agreed.
• The company is under 50 full-time employees at peak.
• The mail is mainly consumer personal data or protected health information with no licensing basis.
• A trustee or assignee controls the assets; read the ABC and receivership IT guide first.
• The archives were already deleted or cannot be read.

If the client is selling the business, the software company sale guide explains how records fit into a transaction.

Next step

Run the six-step inventory on one client this month. If a departed-user cluster or a multi-year archive turns up, register as a partner, then use the network opportunity finder to see which other clients have similar piles.