6 Ways How to Fix an STL File That Won’t Open

There are many instances where an STL file may fail to open when you want to 3D print an object. This can be pretty frustrating for people trying to get a certain model printed. Fortunately, there are various methods you can use to fix this.

To fix an STL file that won’t open, you first want to check whether the file is actually an STL file. If it’s an STL file, then try opening the file directly from the opened slicer software and importing the model. After that, you want to try re-downloading the file since it may be corrupted.

There are more methods to try, so keep reading to learn more about the other methods to help you fix an STL file that won’t open.

How to Fix an STL File that Won’t Open

Here are some ways to fix an STL file that won’t open:

1. Check the file type is an STL file
2. Open the file directly from Cura or chosen slicer
3. Re-download or request a new file
4. Repair the STL file with 3D Builder or similar software
5. Adjust the scale
6. Switch browsers

1. Check the File Type is an STL File

The first thing you want to do if an STL file isn’t opening up properly is to check the file extension is actually an STL file. You might notice that the file is not actually an STL and that’s causing it not to open as normal.

You can check this by seeing the file in your file explorer and checking the “Type” says Stereolithography Mesh in the column or by hovering over the file. With some file types, you can use an online converter to turn them into STL files.

Do a simple Google search for the “*current file type* to STL converter”.

2. Open the File Directly From Cura or Chosen Slicer

Another way to fix an STL file that’s not opening is to open the file directly from your slicer rather than opening it from the file explorer. Sometimes, simply opening up your slicer first can solve the issue of your STL files not opening.

One user complained that he tried opening his STL files after updating Cura, but nothing happened. A user said that that probably happened after he had updated Cura and deleted the old version.

To fix the issue, the person used his uninstaller to find the path to his older version of Cura since it wasn’t shown as an installed program in his programs folder. After that, he deleted all the files tied to the old Cura version, rebooted his computer, and his STL files started to open.

3. Re-Download or Request a New File

You can also fix STL files not opening by re-downloading the file from where you got it from. For example, if you got a file from Thingiverse or MyMiniFactory, the file may not have downloaded properly or may have been corrupted during the download process.

Simply go to the file again, either by going through your browsing history or typing the name again, then re-download the file. If you got the file from someone else, ask them to resend it to you.

4. Repair the STL File with 3D Builder or Similar Software

The STL file might not be opening because the file itself has issues. You can fix some STL files not opening by repairing the file with 3D Builder or another similar software like Meshmixer,Netfabb, or MakePrintable.

These tools work by analyzing the STL file for problems like holes, self-intersecting surfaces,non-manifold geometry, inverted triangles, improper scale etc., and then attempting to fix these issues automatically.

One user complained that Cura crashed every time he tried to open a specific file that was neither too big nor too small (only 162KB). He followed a commenter’s advice and opened it using 3D Builder, which worked.

The commenter added that the mesh of the STL file might have been so broken that Cura could not handle it.

Another user said he bought a Super Star Destroyer model from CGTrader and tried setting it up, but after slicing it, the model became like abstract art. He fixed this issue by repairing the file with Microsoft 3D Builder.

Check out this video by The Machine Bros Solutions on how to repair STL files using 3D Builder.

5. Adjust the Scale

If you created the STL file yourself through a CAD software like Blender, TinkerCAD, or FreeCAD, you can adjust the scale of the model to fix the STL file not opening.

Some STL files might not open due to being too small or large since it creates issues when importing it into your slicer software.

One user downloaded an STL file but could not see the model whenever he imported it into Blender despite zooming far out and in. A user noted that his initial imported dimensions were enormous. He advised the user to scale it down tremendously.

Another user said he consistently failed to get STL files to load into his slicer. He couldn’t see it even after zooming in, nor did he get an error message. After looking into the problem, he found that the model was 1,000 times smaller than it was on Blender.

To fix that, he exported it at 1,000 scale.

Here is an informative video on how to fix STL Export Scale in Blender.

6. Switch Browsers

If you are using an online slicer like TinkerCAD online, you can try switching browsers to fix an STL file that’s not opening. For example, you can try opening the file in Mozilla Firefox if you previously used Google Chrome.

It’s a good idea to clear your browser’s cache and cookies, as this can help resolve some issues that cause the file to open. You should also disable all the extensions that could interfere with the STL file.

One user reported getting import errors every time they tried to load new STL files into TinkerCAD despite the models being simple. One user recommended using Firefox because Google Chrome always seemed to give more issues when importing STL files.

This fixed the problem for the person inquiring.

Another user said that that problem could arise when the internet is poor and recommended using a different browser, private browsing, or even another computer.