When combining presentations, a copied slide may change colour and typography or remain visibly different from its neighbours. Decide whether that difference is intentional before fixing individual text boxes one at a time.

Use desktop PowerPoint for Windows and keep the source deck intact. Create a working copy of the destination presentation. Choose one representative source slide with a title, body text and a graphic so the formatting decision is easy to inspect.

Make the paste choice deliberately

Copy the slide from its thumbnail in the source deck. In the destination deck’s thumbnail pane, paste it after the intended slide and inspect Paste Options.

Microsoft documents two relevant choices. Use Destination Theme adapts the copied slide to the receiving presentation’s theme. Keep Source Formatting retains the original presentation’s theme for the copied slide.

Choose the option that matches the editorial purpose. A unified company presentation may need a common theme, while a clearly identified historical example may need its original appearance. Neither choice establishes that the resulting slide is ready without inspection.

Compare the imported content with the original

Check title wrapping, body text, chart labels and the contrast between text and backgrounds. Confirm that the slide still communicates the same information and that no essential wording has become difficult to read.

View the imported slide beside the preceding and following slides. Look for differences that appear accidental, such as an unexplained colour change in a category used throughout the presentation. Resolve those differences with a consistent meaning, not merely visual uniformity.

If the first choice gives a poor result, undo and compare the alternative before importing the remaining slides. Keep a record of which source deck supplied the content so later updates can be checked against the right version.

Finally, run the combined presentation and inspect its complete sequence. Save a clearly named handover copy after the content and theme choices have been accepted. Copying the slides transfers material; the final review establishes whether it belongs coherently in the new deck.

References: Microsoft: copying and pasting slides.