By Tylar E. · 27 July 2026
How to Unflatten Markups in Bluebeam
Document > Unflatten only works if Allow Markup Recovery was ticked at flatten time. What to do when it was not, and how reversible flattening differs.
The short answer: in Revu, go to Document > Unflatten. It only works if Allow Markup Recovery (Unflatten) was ticked in the Flatten Markups dialog at the time the file was flattened. If it wasn't, the markups are part of the page and cannot be recovered (Bluebeam's documentation).
That checkbox is the whole story, and it is decided by whoever flattened the file — often not you.
How unflattening works in Revu
- Open the flattened PDF in Revu.
- Go to Document > Unflatten.
- Markups from the flattened pass return as editable objects.
The recovery data rides inside the PDF, so it travels with the file. If a subcontractor flattens with recovery enabled and emails you the drawing, you can unflatten it at your end.
Why it often fails
Four reasons, in the order we see them:
- Recovery was never enabled. Bluebeam's own guidance is to flatten without recovery when you want to stop third parties editing your markups — so a file deliberately locked down will not unflatten, by design.
- The file was edited after flattening. Bluebeam publishes a specific troubleshooting note for this: certain actions on a flattened page alter the content and make the markups unrecoverable. Saving through another PDF tool is a common culprit.
- They were form fields. Flattening form fields is permanent in every case. No option changes that.
- It was flattened twice by different people. Each pass has its own recovery setting, and the strictest one wins.
If none of those apply and it still fails, the practical fallback is the previous version of the file. Ask whoever sent it for the pre-flatten copy — that is faster than fighting the PDF.
The habit that avoids the problem
Flatten late, not early. Flattening is a send step, not a working step: mark up, measure, review, and flatten only as the file leaves your hands. A drawing you are still working on has no reason to be flattened, and every reason to stay editable.
If you do flatten mid-project, tick Allow Markup Recovery and tell the next person you did. The setting is invisible to them until they need it.
How we handle it in ContractorCounter
We build ContractorCounter for the contractor half of this workflow — markup, measurement, counts, exports — and flattening works differently here, which is worth knowing if this problem keeps costing you time.
Flattening is reversible without deciding in advance. There is no recovery checkbox to remember, because we do not burn markups into the page. Flatten from Document > Flatten Markups, on the whole drawing or on pages you pick, and the markups stop being selectable so a stray click cannot move them. The records are kept, not destroyed.
Unflatten restores the last batch. Document > Unflatten Markups peels back the most recent flatten with its geometry, styling, page and properties intact. Flatten three times and you unflatten three times, newest first. The full behaviour, including the 5,000-markup and 1,000-page ceilings per pass, is in the flattening and unflattening guide.
You can keep working on a flattened page. New markups added afterwards stay editable and are not swept into the earlier batch.
Two honest limits. Both commands need edit access to the drawing version, so read-only viewers cannot flatten or unflatten — that is deliberate. And this is our own document model, not the PDF's: an exported PDF is a normal PDF, so if you send one to someone in Revu, Revu's rules apply again at that point.
What to use when
| Situation | Best move |
|---|---|
| Sending a final set you do not want edited | Flatten in Revu with recovery off, deliberately |
| Protecting your working copy from stray clicks | Flatten with recovery on, or work somewhere reversible |
| You received a flattened file and need the markups | Document > Unflatten, and if it fails, ask for the pre-flatten version |
| You flatten and unflatten regularly during a job | The checkbox is the wrong tool for this — it is a send-time control, not a working one |
Frequently asked
Can I unflatten a PDF in Adobe Acrobat? No. Unflatten is a Revu feature that relies on data Revu wrote into the file. Acrobat has no equivalent recovery step.
Does unflattening change the drawing itself? No. It restores the markup layer. The underlying sheet is untouched either way.
Can I unflatten just one page? Revu's Unflatten command works on the current document. In ContractorCounter, flatten scope can be a set of pages, and unflatten reverses whichever batch was most recent — so page-scoped flattens come back page-scoped.
Is flattening the same as locking? No, and Bluebeam documents the difference too. Locking stops a markup being moved while keeping it an object; flattening makes it part of the page. Locking is usually what people actually want mid-project — we cover ours in locking and unlocking markups.
