Redact text in PowerPoint before AI reads it

To redact text in PowerPoint before an AI tool reads the deck, take the words out of a duplicate deck instead of hiding them behind a shape. Then go looking in the places a slide never displays: the notes under each slide, any slide marked hidden, the comments pane, the slide master, descriptions written for screen readers, and each chart’s hidden workbook. Microsoft’s Document Inspector clears some of that, not all of it, so it goes last.

A presentation is rarely written for the audience of a chatbot. It was built for a meeting: talking points in the notes, a spare slide hidden for questions, a colleague’s comment asking who rang the client, a chart pasted in from last quarter’s workbook. When someone later asks an AI tool to summarise the deck or turn it into a report, all of that goes with the upload, because the upload is the file and not the slideshow.

In Australia the regulator has spelled out why that matters. The OAIC’s guidance on commercially available AI products warns that once personal information goes into a generative AI product it will be “very difficult to track or control how it is used”. What follows is about making sure the deck you upload holds only what the question needs.

How to redact text in PowerPoint: delete it, never cover it

Search results for this question fill up with plugins and online converters. You do not need either for most decks. What you need is a copy, a fixed order and a clear idea of where text hides. The order below suits a client review from an accounting practice as well as a board pack full of charts.

Step	Where it is in PowerPoint	What it clears
Save a copy	File, Save As	protects the original from removals Undo cannot reverse
Unhide every slide	right click a slide thumbnail, Unhide Slide	slides skipped in the slideshow
Clear the notes	Notes pane under each slide	talking points, phone numbers, reminders
Delete comments	Comments pane, More thread actions, Delete thread	comment text and the reviewer’s name
Check the master	View, Slide Master	text repeated on every slide
Replace charts	paste as Picture	the workbook stored behind a chart
Run the inspector	File, Info, Check for Issues, Inspect Document	properties, leftovers off the slide

PowerPoint for Windows, as the menus are named on Microsoft Support (Australia).

The first row is the one people skip. Microsoft recommends running its inspector on “a copy of your original presentation”, and says some removals cannot be undone. Working on a copy also means the meeting version stays intact for the meeting, and the AI version can lose whatever it does not need without anyone arguing about it.

The rest of the order follows one rule: reveal first, then remove, then inspect. Each step is covered in more detail below, and our guide to redacting in Word walks through the same logic for documents, where tracked changes take the place of speaker notes.

A deck built on last year’s deck

Most client decks start as a copy of an older one. The new client’s name goes on the title slide, the figures get updated, and everything nobody looks at stays as it was: the previous client’s name in a note, a hidden slide from the old engagement, a chart whose workbook still has last year’s rows. Ask where the file came from before cleaning it: a deck with a history needs the full order below, however new its slides look.

Inside a .pptx: the parts no slide shows

Rename a .pptx file to .zip and most computers will open it as a folder, because that is what it is: a zipped bundle of XML files, one per slide, plus separate files for notes, comments, the master, the chart data and the document properties. PowerPoint assembles the slides you see from those pieces. Anything that reads the package directly gets every piece, whether PowerPoint puts it on screen or not.

To show this with something concrete, we built a four slide test deck for an invented bookkeeping practice, then listed the text in each part of the package with a short Python script that uses no Office software at all. Every name in it is made up and has been used in our other guides.

The table below comes straight from that listing. The middle column is what someone flicking through the deck in Normal view would notice; the right column is what the package held. The last row, author and company, is file metadata, which our metadata guide treats in its own right.

Part of the package	Seen in the slideshow?	What our test deck held there
Speaker notes	no	a contact name and a mobile number
Hidden slide	no	a client name and a TFN
Comments and authors list	only with the pane open	two remarks and two reviewers’ names
Slide master	as a line on every slide	“Prepared for” and a client’s name
Chart workbook	only the plotted figures	a column naming a partner
Alt text, and a box off the slide	no	a client named in a shape’s alt text, an old draft line
Document properties	no	the author and the practice’s name

Our invented test deck, 28 September 2026. Text read from the XML, not from PowerPoint.

Speaker notes

Notes are where presenters put what they cannot say on a slide: who to thank, which number the client asked about, the mobile to ring if the video link drops. Microsoft itself describes the Notes section as a place that may hold text you would rather not make public. Each slide’s notes sit in their own file inside the package, and that file travels with every copy of the deck.

The reason notes get so candid is that the audience never sees them. Microsoft’s help on speaker notes explains that during a show the presenter’s monitor displays them and the audience’s screen does not. That is true in the room. It stops being true the moment the file itself is handed to someone, or to something, else.

Hidden slides

Hiding a slide only tells the slideshow to skip it. Microsoft’s help page on hiding a slide is clear that the slide stays in the file even though the show passes over it. In our test deck the hidden slide was an ordinary slide file with one extra attribute set, and its text was as easy to read as any other slide’s.

The slideshow

Slide 3 never appears. The presenter goes from 2 to 4.

The file

Slide 3 is still stored, client name and TFN included.

Microsoft suggests hiding slides that give extra detail for a particular audience, so you can bring them up if someone asks. In a client deck that extra detail is often the most personal part: the fee dispute, the arrears, the complaint history. The slides kept out of the slideshow are frequently the ones that most need to stay out of the upload.

Comments and their authors

Comments carry two kinds of personal information: what the reviewer wrote, and who the reviewer was. PowerPoint keeps a separate list of comment authors, so even a comment that says only “check this” names a person. In our deck, one comment also mentioned a client by first name, which is the sort of remark nobody rereads before sharing.

The slide master and the footer

Text typed on the slide master appears on every slide based on it, and people forget it is there because they did not type it on the slide. A “Prepared for” line with a client’s name, or a footer with the adviser’s name, can sit on the master for years. Microsoft’s explainer on the slide master explains why you cannot delete such an element from Normal view: it lives in Slide Master view.

Alt text and boxes parked off the slide

Alt text is written for screen readers, and alt text for a photo of a person often names them. That description is stored with the object it describes. Microsoft’s Document Inspector also looks for content “dragged off the slide into the off-slide area”, a common home for old draft text. Our test deck had one of each, and both were plain text in the XML.

SmartArt keeps its text twice

A SmartArt graphic stores what you type in a data part and again in a separate drawing part. In our test deck the line on the SmartArt shape, a staff member’s name with a role in front of it, appeared in both parts. A tool that edits one part and not the other leaves a copy behind, so change SmartArt text inside PowerPoint itself and check the saved copy afterwards.

A chart brings its spreadsheet along

When you insert a chart in PowerPoint, or paste one from Excel with an embed option, the figures come with a workbook of their own stored inside the .pptx. You see it when you choose Edit Data.

That workbook is a whole spreadsheet, not only the cells the chart plots, and whatever else was on the sheet comes too. Our invented deck proves it: two clients’ fees on the slide, and inside the workbook a third column naming a partner.

Microsoft’s guidance for inserting Excel data in PowerPoint is candid about the embed option, warning that it can hand over more of your Excel file than you meant to share. Its Document Inspector reports embedded charts without deleting them, and suggests replacing such an item with “a static picture”.

Seven reviewers read the printout

Australia already has a well documented case of chart data travelling where nobody looked. Early in 2014 the federal immigration department put a statistics summary on its website in two formats, and the Word one carried the spreadsheet its graphs had been built from. That spreadsheet listed roughly 9,250 people seeking asylum by full name, with dates of birth and detention details. The OAIC’s own motion investigation report sets out how it happened.

The detail that matters for anyone checking a deck is the review process. According to the OAIC, departmental policy had the report cleared by seven reviewers in hard copy, and most of the people involved did not know Excel data could be embedded in a Word file. The policy did say graphs should go in as pictures, but did not explain why.

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Every reviewer looked at the printout, which is exactly the view that cannot show embedded data. A deck checked on screen has the same blind spot. The Excel version of this guide covers the workbook side.

Paste a picture instead

For a deck going to an AI tool, the rows behind a chart are rarely what the question is about. A picture keeps the look of the slide and drops the workbook.

In the copy, select the chart, cut it, and use Paste, Picture. According to Microsoft’s instructions for copying from Excel to another Office program, a chart pasted that way can no longer be edited or updated, and here that is exactly the aim. Bear in mind that OpenAI says ChatGPT drops images from most uploaded files, so a pictured chart may give it nothing to read. If the model needs the figures, type the few it needs into a table on the slide.

Other files dropped into a slide

Besides charts, Insert, Object can place a whole Word document, a spreadsheet or another presentation on a slide, showing as an icon or as its first page. If that document is a draft, settle its edits before it goes in, since a Word file keeps tracked changes until they are accepted or rejected.

The file inside is complete, with its own hidden parts, as our guide to redacting in Word shows for a .docx. Microsoft’s inspector reports embedded files and objects and leaves them where they are, so open each one in the copy, read it, and remove any the AI question can manage without.

Shapes on top, white font and cropped photos

The quick fixes people reach for in PowerPoint all work on appearance, unlike covers burned into a NSW licence photo. A black rectangle over a name, a highlight set to black, text recoloured to match the background, a photo cropped until the client’s face is gone: each one changes what the slide looks like and leaves the content where it was.

Text under a shape is still text in the slide’s XML, in reading order, and a tool that pulls out the text has no reason to look at the shape at all. On the first slide of our test deck we laid a filled black rectangle over the client’s name; the listing still returned the name. Recoloured text is the same characters in another colour.

Cropping is less obvious, and Microsoft is direct about it on its page on cropping a picture: cropped parts “are not removed from the file, and can potentially be seen by others”. The fix it gives: select the picture, then Picture Format, Compress Pictures, and tick Delete cropped areas of pictures. Deletions can be undone only until the file is saved.

The slide

A black bar where the client's name was.

The file

The name, in full, under a separate shape.

Exporting the deck to PDF and blacking out lines there does not help either. The boxes are a new layer on top of text that is still in the PDF, as the test file in our guide to redacting a PDF demonstrates. Microsoft’s PDF export options also let you include hidden slides and comments, so a PDF made in a hurry can carry more than the slideshow did.

Redact a PowerPoint deck on a copy, step by step

The order matters because each step can uncover work for the next. Unhiding a slide shows you notes you had not seen; opening the comments pane shows you a name you then search for across the deck. If you inspect first, you remove properties and notes but leave hidden slides and chart workbooks untouched, and the result looks finished when it is not.

Deal with hidden slides first

In the copy, open the thumbnail pane on the left in Normal view. Hidden slides are the ones whose number is struck through. Right click it and choose Unhide Slide, then read it as if it were going on screen. Most hidden slides in a client deck exist for one audience only: fee discussions, backup detail, a slide about a complaint. If the AI question does not need it, delete the slide rather than hide it again.

Notes, comments, then the master

With every slide visible, read the notes one by one, because notes are the part of a deck least likely to have been written carefully. Delete the whole Notes section on a slide if the question does not need it. Then select Show Comments on the Review tab and delete each thread; Microsoft’s help on managing comments describes More thread actions, then Delete thread.

After that, go to View, Slide Master and read the master, then every layout that hangs off it. Delete any client name, adviser’s name or “Prepared for” line, and check the footer placeholders. Close the master view and page through the slides again to confirm the line has gone from all of them.

Charts, pictures and alt text

Swap every embedded chart for a pasted image of it, as described earlier. For photos, decide whether the model needs them at all: a staff photo, a photographed drivers licence or a picture of a client’s property adds nothing to a question about fees. If a photo does go to a chatbot on its own, what each provider keeps from it differs more than people expect.

Any picture you keep may carry a description for screen readers: open it with right click, View Alt Text, and take out whoever it names. Microsoft’s page on alternative text lists shapes, charts and SmartArt among the objects that can carry it, so check those too.

Inspect Document at the end

Only then open File, Info, Check for Issues, Inspect Document on the copy, select Inspect and choose Remove All beside each result you want gone. Microsoft’s page on inspecting presentations lists what the PowerPoint inspector covers, and the gaps are as useful as the list.

Inspect Document checks	Not on its list, or found but not removed
Comments and ink annotations	hidden slides
Document properties and personal information	text typed on the slide master
Revision tracking data	alt text on pictures and shapes
Invisible content on the slide	objects covered by other objects
Content off the slide (not animated)	animated objects parked off the slide
Presentation notes	pictures pasted into the notes
Custom XML data	embedded charts and files (found, not removed)

Microsoft Support (Australia), Document Inspector for PowerPoint, read 28 September 2026.

When the inspector has finished, choose Reinspect to make sure the results are clear. For the properties that remain, our guide to removing metadata explains what an author field and a company field say about a file, and why they matter when the whole file goes to an AI tool.

Revision data and the setting that stays on

Decks that several people edit in the cloud with Microsoft 365 also carry revision tracking data: who changed the file and when. Microsoft notes that an older copy of PowerPoint may not detect revision data added by a newer one, so run the inspector in a current version. After a clean, PowerPoint keeps removing personal information each time the copy is saved, until someone changes that setting from the notice it shows.

Check the cleaned copy before it leaves

A clean you cannot check is a clean you are taking on trust. Close the copy, reopen it, and look at it the way a stranger would: every slide in Slide Sorter view, the notes pane on each, the comments pane, the master. Next, search the deck (Home tab, Editing group, Find and Replace) for the client’s surname, the first name on its own, the practice’s name and the first digits of a mobile number.

For a check that does not depend on PowerPoint at all, rename a copy of the cleaned file to .zip and open it. Look in the folders for notes, comments, charts and embeddings, if they are still there, and open anything left inside with a text editor. You are looking for the same names you searched for, in places the slideshow never showed you.

If the deck has already gone

If the full deck has already been uploaded, delete the conversation and check whether the service keeps chats for training or review under your plan. Then treat it as a possible privacy incident and record what was in the file. Our guide on whether putting client data into ChatGPT is a data breach covers the Australian notification questions.

What ChatGPT takes from an uploaded deck

OpenAI’s file uploads FAQ says ChatGPT can work with presentations and gives, as an example, uploading a PowerPoint deck and asking for feedback on its content. Among the uses it lists is extracting metadata such as the author and creation date. Outside the Enterprise feature for pictures in PDFs, it says ChatGPT will “extract digital text” from a file and “discard any images”.

That settles one point and leaves another open. Text in the file is what the model works from, so text hidden from the slideshow is exactly the kind of content that counts.

OpenAI does not say which parts of a .pptx its extraction reaches, and we have not tested it against our deck. The safe reading is to treat every line of text saved in the file as sent, whichever service you use.

For our test deck that means 39 parts in the package, 15 of them holding a person’s name, and only 3 of those 15 being slides the audience would see. Our guide to what ChatGPT keeps and deletes covers what happens after the upload.

39parts in our test .pptx

15held a person's name

3of those were slides on screen

Copilot in PowerPoint raises its own questions about who can reach a file through it, and our Copilot guide deals with those separately.

Board packs, client reviews and APP 6

Decks in Australian workplaces carry a predictable set of identifiers: a tax file number on a slide about a client’s lodgement, a Medicare number in a clinic’s case review, an NDIS participant’s name in a provider’s quarterly report, home addresses in a property manager’s portfolio summary. Our list of personal identifiers to remove before AI sets out the Australian ones and where they turn up.

The legal question is whether uploading the deck is a use or disclosure the business can justify. The OAIC’s guidance works through an example of an insurer putting a customer’s details into a chatbot and treats that as a disclosure to the chatbot’s owner, which has to satisfy APP 6. A deck prepared for one client meeting was rarely collected with a chatbot in mind.

Board packs deserve a second look because they gather names from every part of the business: a complaint with the customer’s name, a staff matter, a debtor list turned into a chart. Those items are often the ones parked in notes or on hidden slides before the meeting, which is why the clean has to reach them.

Two Australian details sharpen this for particular sectors. Tax file numbers are covered by their own rule under the Privacy Act, set out in the TFN section of our Word guide. Health information and other sensitive information need consent in most cases, as set out in our sensitive information guide. If your decks are NDIS reports, our page for NDIS providers is written for that sector.

Nonimo on the September quarter deck

In Nonimo you select the presentation in Finder on a Mac or File Explorer on Windows and press your Nonimo key. The clipboard then holds the text of the slides, hidden ones included, and the speaker notes, each detail covered, ready for the chatbot; paste its answer back and the names return. Dropped on the Nonimo window, the deck can also be downloaded as the same PowerPoint file, covered. Working from an older .ppt? A quick Save As to .pptx and it’s ready.

A three slide test deck with notes:

BEFORE (text read from the .pptx; slide 3 is hidden, the last three lines are the notes)
September quarter client review
Client: Maree Quintrell
Email: m.quintrell@example.com

Open jobs
Client	Mobile	Email	Service
Tamsin Achterberg	0491 570 156		BAS lodgement
Mirela Quennell		mirela.quennell@example.com	Bookkeeping

Not for the client
Client: Tobias Rendle
TFN: 000 000 000

Contact name: Bronwyn Tallis
Mobile: 0491 570 110
Confirm the BAS figures before the call.

AFTER (Nonimo, what goes on the clipboard)
September quarter client review
Client: [PERSON_1]
Email: [EMAIL_1]

Open jobs
Client	Mobile	Email	Service
[PERSON_2]	[PHONE_1]		BAS lodgement
[PERSON_3]		[EMAIL_2]	Bookkeeping

Not for the client
Client: [PERSON_4]
TFN: [TFN_1]

Contact name: [PERSON_5]
Mobile: [PHONE_2]
Confirm the BAS figures before the call.

Give the notes a quick read before you paste. The link back to each person stays on your computer, which makes this pseudonymisation; our security page says what Nonimo stores.

Sources

• OAIC, Guidance on privacy and the use of commercially available AI products. Personal information put into generative AI products is very difficult to track or control and potentially impossible to remove; the insurer example treating chatbot input as a disclosure that APP 6 must permit; sensitive information generally requires consent. oaic.gov.au
• OAIC, Department of Immigration and Border Protection: own motion investigation report. The Word version of the detention statistics report published on 10 February 2014 with an embedded Excel spreadsheet; about 9,250 asylum seekers, including full names and dates of birth; clearance by seven reviewers in hard copy; staff unaware that Excel data could be embedded; the unexplained policy to paste graphs as pictures. oaic.gov.au
• Microsoft Support (Australia), Remove hidden data and personal information by inspecting documents, presentations, or workbooks. The PowerPoint inspectors and their limits; notes that may hold text not meant for sharing; off slide content; embedded charts found but not removed; the advice to inspect a copy and the warning on Undo; revision tracking data and older versions; PowerPoint removing personal information on later saves. support.microsoft.com
• Microsoft Support (Australia), Hide or show a slide and Add speaker notes to your slides. “A hidden slide remains in the file”; Unhide Slide from the thumbnail pane; hiding slides that give extra detail for some audiences; notes visible to the presenter and not to the audience. Hide a slide · Speaker notes
• Microsoft Support (Australia), Add, change, hide, or delete comments in a presentation. Show Comments on the Review tab; More thread actions, Delete thread. support.microsoft.com
• Microsoft Support (Australia), What is a slide master in PowerPoint?. Elements defined on the master are edited in Slide Master view, not Normal view. support.microsoft.com
• Microsoft Support (Australia), Insert and update Excel data in PowerPoint. The Embed paste option and its warning about giving more access to the Excel file than intended. support.microsoft.com
• Microsoft Support (Australia), Copy from Excel to another Office program and Change the data in an existing chart. Embed and Picture paste options for charts; Edit Data for embedded and linked charts. Copy from Excel · Change chart data
• Microsoft Support (Australia), Find and replace text (PowerPoint). Home tab, Editing group, Find and Replace. support.microsoft.com
• Microsoft Support (Australia), Crop a picture in Office. Cropped parts stay in the file; Compress Pictures, Delete cropped areas of pictures. support.microsoft.com
• Microsoft Support (Australia), Add alternative text to a shape, picture, chart, SmartArt graphic, or other object and Save PowerPoint presentations as PDF files. View Alt Text; the PDF options to include hidden slides and comments. Alt text · Save as PDF
• OpenAI Help Center, File uploads FAQ. Presentations among supported files; metadata extraction as a use; digital text extracted and images discarded outside PDF visual retrieval. Read in the Wayback Machine copy of 18 September 2026, as the live page refuses automated requests. help.openai.com