How-to guide · how to recover a corrupt dwg file

How to recover a corrupt DWG file

DWGDXFFree1,028 words

By Sumana Kumar · Published 26 Jul 2022 · Updated 7 Dec 2024

A drawing that throws an error on open, or opens to a blank screen, or crashes AutoCAD the moment it loads, is corrupt — its internal structure has been damaged, usually by a crash mid-save, a network glitch, or a bad transfer. The good news is that DWG corruption is often recoverable, and AutoCAD ships with the tools to do it without any third-party software.

This guide works from the gentlest fix to the most thorough: RECOVER for the host file, RECOVERALL when external references are involved, and the Drawing Recovery Manager when a crash interrupted your work. We will also cover the simple precautions — backups and the .bak file — that turn a lost afternoon into a five-minute reload. The same methods apply whether the casualty is a full project sheet or a single block file from your symbol library.

Step 1 — Try RECOVER first

Do not keep double-clicking a file that will not open; that can make things worse. Instead, start AutoCAD with no drawing (or any drawing) open, type RECOVER, and press Enter. Browse to the damaged DWG and select it. RECOVER forces the file open even when its header is damaged, then runs a full audit pass and reports what it found and fixed in the text window (press F2 to read the whole log).

If RECOVER succeeds, immediately SAVEAS the result under a new name so you keep the original. Then run PURGE and AUDIT once more on the recovered file to clear out any orphaned objects the repair left behind.

Step 2 — Use RECOVERALL when xrefs are attached

If the drawing references external files (xrefs) and the corruption might live in one of them, RECOVER alone will not catch it. Run RECOVERALL instead. It recovers and audits the host drawing and every nested external reference in the tree, so a problem hiding in a referenced base plan gets fixed too.

RECOVERALL produces a report listing each file it processed and the errors per file. This is the right tool for coordinated drawing sets, where a single damaged xref can make several otherwise-healthy sheets fail to open or display.

Step 3 — Check the Drawing Recovery Manager after a crash

When AutoCAD crashes, it tries to preserve your unsaved work. Next time you launch, the Drawing Recovery Manager opens automatically (or type DRAWINGRECOVERY to open it). It lists the drawings that were open when the crash happened and offers the most recent recoverable version of each — typically the automatic save file (.sv$).

Double-click an entry to open the best available version, check that your recent work is present, and SAVEAS it back over your working file once you are happy. The recovered version is often only minutes behind your last manual save, depending on your autosave interval.

Step 4 — Fall back to the .bak backup file

By default AutoCAD writes a backup of the previous version each time you save, with a .bak extension, in the same folder. If RECOVER cannot rescue the current DWG, the .bak is your next hope: it holds the drawing as it was at the save before the one that corrupted it.

To use it, copy the .bak file, rename the copy's extension to .dwg, and open it. You lose only the changes made between that save and the corruption — usually a small price compared with rebuilding from scratch. If you do not see .bak files, check that the ISAVEBAK system variable is set to 1 so backups are being created.

Step 5 — Salvage geometry by inserting into a clean drawing

When a file is too damaged for RECOVER but still opens partially, you can sometimes rescue the good geometry by transplanting it. Open a new blank drawing from a clean template, run INSERT, and browse to the damaged DWG to bring it in as a block. Because INSERT reads the geometry without inheriting all of the host file's broken settings, the clean drawing often ends up healthy.

Once inserted, EXPLODE the block if you need the entities editable, then audit and purge the new file. It is a last-resort move, but it frequently recovers the drawing content even when the original file structure is beyond repair.

Preventing the next corruption

Most DWG corruption is preventable. Keep automatic save on with a sensible interval so the Drawing Recovery Manager always has something recent to offer. Leave .bak creation enabled. Save to a local drive and copy finished files to the network or cloud rather than working live off an unstable network share, which is a frequent cause of mid-save corruption.

Finally, audit your reusable base files and shared block libraries periodically. A clean source file rarely corrupts, and when a problem does appear it is contained to one sheet rather than seeded across a whole project. A small block downloaded as a known-good DWG is a safer building block than one salvaged from a damaged drawing.

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Questions

Frequently asked

My DWG won't open at all. What do I do first?+

Open AutoCAD without the file, then run RECOVER and browse to the damaged DWG. RECOVER forces the file open and audits it. If the drawing has external references, use RECOVERALL instead so referenced files are checked too.

What is a .bak file and how do I use it?+

A .bak is AutoCAD's automatic backup of the previous saved version, stored beside the DWG. If the current file is unrecoverable, copy the .bak, rename the copy to a .dwg extension, and open it. You lose only changes made after that earlier save.

Where does AutoCAD keep my work after a crash?+

In automatic save files (.sv$). The Drawing Recovery Manager opens after a crash and lists the recoverable versions of the drawings you had open. Open the best version, confirm your recent work is there, and save it over your file.

Can I recover just the geometry if the file is too damaged?+

Yes. Open a clean blank drawing and INSERT the damaged DWG as a block. Reading the geometry into a healthy file often leaves the corrupt settings behind. Explode the block if you need editable objects, then audit and purge the new drawing.

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