Why won't my DWG file open?

Start here: check the DWG version

The single most common reason is that the drawing was saved by a newer AutoCAD than the software you're opening it with. AutoCAD and AutoCAD LT open their own DWG format and every older one, but nothing newer. AutoCAD 2017, for example, can't open a drawing saved in the AutoCAD 2018 format, and many third-party viewers lag several versions behind.

Every DWG records its format in its first six bytes, such as AC1032 for the AutoCAD 2018 format or AC1027 for 2013. Drop the file into the free version checker to read it instantly. Nothing is uploaded.

Check my DWG's version

Fix: ask the sender to use Save As and pick an older format such as "AutoCAD 2013 Drawing", or convert it yourself with Autodesk's free DWG TrueView (Windows) or the free ODA File Converter (Windows, macOS and Linux). If you only need to look at it, a viewer that reads the newest format, such as Caddis, skips the conversion entirely.

1. The file is damaged or didn't finish downloading

Email gateways, sync tools and interrupted downloads can truncate a drawing. A tell-tale sign is a file much smaller than the sender expects, or an error mentioning an invalid or corrupt drawing.

• Download it again, or ask for it zipped, which protects the file in transit and makes truncation obvious.
• In AutoCAD, run RECOVER on the file, then AUDIT once it opens. Both are built-in repair commands.
• If the original is gone, look for a backup next to it. AutoCAD writes a .bak file on every save and .sv$ autosaves, and renaming either to .dwg often gives you a recent working copy.

2. It isn't actually a DWG

Several CAD-adjacent formats look similar in a file list. DWF is Autodesk's lightweight publishing format, not a drawing; DWT is a template (a real DWG under a different extension, so renaming a copy to .dwg works); DXF is the exchange format; and .bak is a backup. A file renamed to .dwg by mistake won't open in anything.

The version checker also tells you when a file named .dwg doesn't start with a DWG version code, which usually means it's damaged or a different format renamed.

3. It opens, but the screen is blank

A drawing that opens to an empty screen usually isn't empty. The view is pointed at the wrong place.

• Zoom to extents. In AutoCAD type ZOOM, then E. In most viewers, look for "fit" or "zoom extents". A single stray object far from the plan can make the real drawing a dot in the corner.
• Check the layers. Layers that are off or frozen hide their content. Turn them all on to see what's there.
• Look at the layouts. Some drawings keep content in paper-space layouts rather than model space. Caddis displays model space, so a drawing whose geometry exists only in a layout will look empty there.

4. Parts of the drawing are missing (external references)

Architectural and engineering sets often assemble one sheet from several files using external references (xrefs). If you received only the host drawing, the referenced backgrounds, title blocks or images are missing, and AutoCAD lists them as unresolved in the External References palette.

Fix: ask the sender to use eTransmit, which packages a drawing with every file it references, or to bind the xrefs into the drawing before sending.

5. Objects show as boxes or are missing (proxy objects)

Drawings from AutoCAD's vertical products (Civil 3D, Plant 3D, MEP, Architecture) contain custom objects that plain AutoCAD and most viewers can't interpret. They appear as proxy graphics, simplified boxes, or not at all.

Fix: install the matching Autodesk Object Enabler, or ask the sender to export to plain AutoCAD (in Civil 3D: Export to AutoCAD), which converts custom objects into standard geometry everyone can read.

6. Text is wrong, garbled or in the wrong font

DWG text references fonts by name, including AutoCAD's own SHX fonts. When a font isn't installed, the software substitutes another, which can change spacing or turn special characters into question marks. The drawing isn't broken. Ask for the font files, or have the sender convert text to geometry before sending.

7. The file is very large

Survey, civil and point-cloud-heavy drawings can be hundreds of megabytes and overwhelm phones and older laptops. Purge unused content (PURGE in AutoCAD), detach point clouds you don't need, or open it on a desktop. Caddis tells you when a drawing is too large to show in full detail, rather than silently dropping geometry.

8. It's older than Release 14

Drawings saved before Release 14 (1997), such as AC1009 (Release 11/12) and AC1012 (Release 13), use older file structures that many modern viewers don't read. Caddis doesn't support Release 11/12 files, and Release 13 support is untested. Current AutoCAD and the ODA File Converter can save them as a modern DWG.

9. Your app doesn't support DWG at all

Photo viewers, Office apps and most phone file browsers can't display DWG. On iPhone, open the file from the Files app into a DWG viewer such as Caddis. On any computer, the free Caddis web viewer opens DWG locally in the browser.

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