⚒ Repair PDF

Repairing a PDF attempts to recover a file that will not open or displays errors, by rebuilding its internal structure so a viewer can read it again.

What repairing a PDF does

PDFs can become corrupted by an interrupted download, a crashed program, or a faulty transfer, leaving the internal index broken even though the page data survives. Repair rebuilds that structure and re-links the content, which often restores access to a file that other viewers reject.

A PDF keeps a table that tells viewers where each page and object lives inside the file; when that table is damaged, an otherwise-intact document can refuse to open. Rebuilding it lets a reader find the content again. Repair works best when only the structure is broken and the page data is still present, so a file that was merely interrupted often recovers fully, while one that was badly truncated may come back only in part.

When to try repairing a PDF

• A file gives an error such as damaged or cannot be opened.
• A download or copy was interrupted and the PDF now fails to load.
• A viewer shows blank pages where content should be.
• A file works in one program but breaks in another.

How Slate repairs PDFs locally

Slate parses whatever valid content it can find in the file and reconstructs a clean PDF on your device, with nothing uploaded. Repair works best when the underlying page data is intact and only the structure is damaged; severely truncated files may only recover in part.

Tips for the best recovery

• Try repairing the original file rather than a re-saved copy, which may have lost more data.
• If only some pages recover, extract those to salvage what you can.
• Keep a backup of the damaged file in case a different approach helps later.
• Re-download the source if you can, since a fresh copy may not be corrupted at all.