Remove a PDF's metadata (and what it reveals)

What a PDF's metadata reveals

A PDF contains information that is invisible on screen but readable by any reader: the author's name, company, document title, the software used to create it, and the creation and last-modification dates. Some files also keep a revision history or hidden layers that remain present even when they no longer appear on display.

A contract exported from a work computer can therefore reveal the name of the employee who drafted it, the name of their company, or the word-processor version used internally, even if the file was renamed before sending.

• Author: name of the person or account that created the file.
• Company: name of the organization entered in the software's preferences.
• Software and version: for example a word processor, a layout tool or a specific scanner version.
• Creation and modification dates.
• Revision history: in some formats, successive changes remain accessible.

View the metadata before removing it

Before cleaning a file, it is best to know what it contains. On a Mac, the Finder's “Get Info” window (File → Get Info, ⌘I) mostly shows system information (size, dates); its “More Info” section can also display a PDF's title and authors, but not all of its internal metadata. To see it, open the file in Adobe Acrobat (File → Document Properties) or in Preview (Tools → Show Inspector, ⌘I), which shows the title, author and subject among other fields.

On Windows, the “Details” tab of the file's properties shows some of these fields. For a fuller check, including embedded XMP data, a command-line tool such as exiftool remains the most reliable reference.

Remove metadata with Adobe Acrobat

Acrobat Pro is the most complete tool for this job, because it also finds hidden layers, attachments, comments or deleted content still present in the file, not just the author and title fields.

1. Open the PDF in Acrobat Pro.
2. Open the redaction tool (All tools → Redact a PDF, or Tools → Redact in earlier versions), then choose “Sanitize document”.
3. To choose for yourself what goes, select “Remove selectively”: Acrobat lists the metadata, attachments, comments, hidden layers and other hidden information found in the file. Tick the items to delete.
4. Click “Remove”, then save a copy of the file: the removal only becomes final when you save.
5. Check in File → Document Properties, Description tab, that the author, title and company fields are empty.

This feature only exists in Acrobat Pro, not in the free Acrobat Reader.

Remove metadata with Preview on a Mac

Unlike Acrobat, Preview has no dedicated feature for removing metadata; it can, however, redact the text of the pages (see redacting with Preview). You can view some fields (title, author, keywords) via Tools → Show Inspector (⌘I), but nothing in the interface lets you clear them directly. Two practical solutions on a Mac:

1. Use a command-line tool such as exiftool (exiftool -all= file.pdf), which clears almost all metadata in one command. Caution: on a PDF, exiftool writes its changes as a reversible incremental update, and the old values remain in the file. Rewrite it afterwards, for example with qpdf --linearize input.pdf output.pdf, otherwise they remain recoverable.
2. Print the PDF virtually (File, Print, then Save as PDF), which often regenerates a file without the original metadata.

Remove metadata with LibreOffice

LibreOffice can open a PDF in its Draw module and re-export a cleaned file, for free and offline.

1. Open the PDF with LibreOffice Draw (right-click the file, then Open With).
2. Go to File, Properties, General tab, and click Reset to clear the author, title and keywords.
3. In Tools, Options, LibreOffice, Security, turn on the option “Remove personal information on saving”.
4. Re-export the file via File, Export as PDF.

Online tools: what they do and their limits

Services such as Smallpdf, iLovePDF or UPDF offer cleaning or compression features that remove some of the metadata. Convenient for a document with no confidentiality stakes, they require you to send the file to a remote server, which raises questions for a contract, a medical file or a court document.

Always check the privacy policy of the service you use, and keep sensitive documents for local processing whenever possible.

Anonymize the author of a PDF

The author's name often hides in several places in the same file, and you need to deal with all of them:

• The document properties: the Author field, visible in Acrobat's File → Document Properties or in Preview's inspector.
• The XMP metadata: a second set of metadata embedded in the file, which usually repeats the same information and which not all readers display.
• Comments and annotations: each one carries an author name, by default the user's login name in Acrobat.

To remove them, use the tools described above. In Acrobat Pro, “Remove Hidden Information” clears both the metadata and the comments. With exiftool, the properties and XMP metadata are emptied in one command, provided you then rewrite the file with qpdf; comments have to be deleted separately, in your PDF reader. LibreOffice lets you reset the properties before re-exporting the file. Finally, check the result: the Author field must be empty, and no comment should remain.

Metadata and anonymization: two different problems

Removing the metadata is not enough to make a document anonymous. Metadata concerns the file's properties; the visible text (names, addresses, phone numbers, case numbers) remains readable until it has been redacted. The two operations complement each other: clean the metadata, then redact the sensitive content if the document must be shared without identifying the people concerned.

Our guide to anonymizing a PDF details the complete method, with free solutions and dedicated software. If the starting document is a scan or a photo rather than a text PDF, the procedure also changes: see how to anonymize a scanned PDF.

AnonymFiles handles both problems at once: on PDFs containing text, it actually deletes the redacted passages and removes metadata, annotations, forms and links along the way (see the list of items removed at export), for an entire folder at a time. Once installed, it works offline, with no account, no online license check, no telemetry and no cloud chat, with a review of each original next to its copy before export; it is coming soon for Apple silicon Macs and Windows. Scans are read by local OCR, and a final check with exiftool or the file's properties remains a good habit.

Check that the metadata is really gone

After cleaning, reopen the file and check its properties again. No tool works 100% on every PDF: some formats keep metadata in compressed streams that only a tool like exiftool detects. If you cleaned the file with exiftool, check the version rewritten by qpdf: in the file merely modified by exiftool, the old values remain recoverable even if your reader no longer shows them. To be safe, always review the result before sending a sensitive document: no automatic tool is 100% reliable.