To anonymize an Outlook email before giving it to ChatGPT, Claude, Gemini or Copilot, save it as a .msg file, add the file to a ClientSafe case, review the names, addresses and numbers it finds, and copy the safe copy into the chat. The AI sees placeholders such as Person_1. When its answer comes back, ClientSafe puts the real names back on your PC.

A printed email with a clipped attachment page and an envelope on a light desk.

What one Outlook email carries

A .msg file is Outlook's own format for a single item. Microsoft's specification says it holds the message with all its properties, including its attachments. For anonymizing, these are the parts that identify people:

  • The header lines. From, To and Cc hold names and email addresses, and the subject often holds a name too.
  • The body. Names in the greeting and the text, phone numbers, account numbers, addresses.
  • The signature. Full name, job title, company, direct line, office address.
  • The quoted replies. Everything below "On Monday, Maria Lopez wrote:" repeats earlier messages, each with its own header and signature.
  • The attachments. They travel inside the file, and their file names can carry a name.

Pasting only the body leaves the header lines behind. Deleting names by hand misses the quotes. The checklist of what to remove before sending documents to AI covers the general case. This article is about the .msg file itself.

Get the .msg file out of Outlook

Which steps you need depends on the Outlook you use.

  • Classic Outlook for Windows. Double-click the message to open it, select File, then Save As, and pick a file type in the "Save as type" list. Microsoft's guide describes these steps. The type to choose is Outlook Message Format (.msg).
  • Classic Outlook, several messages. In the message list, select the messages and drag them into a folder in File Explorer. Microsoft's support forum answers describe this as saving one .msg file per message.
  • New Outlook for Windows and Outlook on the web. Select More actions, then Save as. Microsoft's page says Outlook on the web saves the message as an .eml file. For new Outlook, answers on Microsoft's forum say the same: it saves .eml, not .msg.

If you are on new Outlook and only get .eml, you do not need to switch back. ClientSafe reads .eml files as well as .msg, and the steps below are the same. The guide to summarizing an email thread covers the .eml route. Microsoft's statements about what each version can save change from release to release, so if a menu looks different on your screen, trust the menu.

Two habits make the files safer to handle:

  • Rename the files before you add them. Outlook usually suggests the message's subject as the file name, and subjects carry names: "Lopez - loan documents". Use "Message_01" and so on.
  • Keep one folder per client, outside any folder that syncs to a shared drive.

Save the latest message of a thread first, since it usually quotes the earlier ones. Save earlier messages separately if the quotes are cut short.

Add the emails to a case

  1. Create a case for the client in ClientSafe and add the .msg files.
  2. Review what it found: names, companies, addresses, phone numbers, email addresses, account and ID numbers, dates of birth. Untick the matches that are not personal data. Mark anything it missed, such as a nickname used in one reply or a name in the subject line.
  3. Copy the safe copy, or save it as a Markdown .md file.

Inside one case, the same person gets the same placeholder in every message: in the From line, in the greeting, in the quoted reply and in the signature. The AI can follow who wrote what. The details are in working with a whole case. Documents are processed on your PC.

Attachments

If the AI needs what is inside an attachment, save the attachment from Outlook and add it to the same case as its own document, where it gets the same placeholders as the emails.

A file name can give a name away even when the message is clean: "Lopez_passport.pdf". If a name like that shows up in the safe copy, mark it in the review.

Ask the AI

Paste the safe copy into ChatGPT, Claude, Gemini or Copilot with a prompt that says what you need. For example:

Below is an email from Person_1, one of our clients, to Person_2.
Names like Person_1 are placeholders: keep them exactly as written.
Draft a polite reply that answers each question and lists
what we still need from Person_1.

Keep the placeholders in the answer. If the AI rewrites "Person_1" as a made-up name, the restore step cannot match it.

Restore the names in the answer

Paste the AI's answer into ClientSafe in the same case, and the real names come back. Read the restored draft before it goes anywhere: it is a client document now. Our guide to restoring real names covers what to check.

Frequently asked questions

Can I give the AI the .msg file itself?

You can, but it is a file with the real names, headers and attachments in it. The point of the safe copy is that the AI only ever sees placeholders.

Why not copy the text out of Outlook?

Copying the body leaves out the From, To and Cc lines, and they hold many of the names and addresses. The saved file has them, so they can be replaced too.

Does it matter that the email is in HTML or plain text?

For this workflow, no. Add the file and review the result. If a message looks empty or cut short in the safe copy, open it in Outlook and check the original.

What if a name appears only in an image in the email?

Text in pictures and scans is read too, but check the review list for it. A signature saved as a picture is a common place for a name to hide.

ClientSafe replaces names, email addresses and phone numbers in saved Outlook emails with placeholders on your PC, and puts the real names back into the AI's answer. Detection is not perfect, so review the list before you copy.