Hello @loyal_Rose7a4e,
I hope you are doing well, and thanks for reaching out. Sorry for the trouble you had.
Could you please share more details about the issue?
What exact Acrobat product and full version/build is the affected person using (Menu > Help > About Acrobat)?
Is the Dropbox PDF being opened directly from the synced Dropbox folder, or downloaded locally before editing?
When the corruption occurred, were all three people editing/commenting on the same PDF at the same time, and did Dropbox report a conflicted copy/version?
Does Error 43 appear in Acrobat itself, and if so, what is the exact wording of the error message?
Suggestions:
Go to https://adobe.ly/4xBzRLn, find the PDF, click the "..." next to it, and open Version history. Pick a version from before it broke and choose Roll back / Restore. This is your best shot. Dropbox keeps older versions (how far back depends on your plan, usually at least 30 days).
Look in the same folder for a file with "conflicted copy" in its name (for example ", Proof (Jane's conflicted copy 2026-09-03).pdf"). Dropbox does not announce these; you have to spot them, and one may hold good content.
How to stop it happening again
The safe way to have several people comment on one PDF is not to have everyone open and save the same file in Dropbox. Instead, in Adobe Acrobat, use Share (Share for review / for comments): you send everyone one link, they all comment on the same online copy at once, and Acrobat keeps everyone's comments together safely; the file itself is not being overwritten by three people. If you would rather not use a link, the simple alternative is to take turns (only one person edits and saves at a time), or have each person comment on their own copy and then merge the comments afterwards. Check this article for more details: https://adobe.ly/4cuoEnD
Also, ensure you have the latest version of Acrobat installed on the machine: 26.002.21869, Planned update, Aug 31, 2026. Check for any pending updates from Menu >Help > Check for updates, install any pending updates, restart the app, and the computer. And try again.
I hope this helps, and please reach out if you experience any issues or need any assistance.
Regards,
Anand Sri.