Upload Failed. Unsupported File Type

[Virtality]

Well, Bambu is back at it again, seemingly changing upload parameters without any clear message, guideline, or explanation, leaving creators to guess what MakerWorld wants.

I have a sneaking suspicion that more and more of these quirks and bugs are the result of real software development being replaced or rushed with AI-assisted work, because how else do you explain the level of broken, inconsistent issues we keep seeing on MakerWorld? The creator experience has been getting noticeably worse over the last six months. It honestly feels like the platform is moving backward.

Now for the actual reason for this post:

I am receiving a new error:

“Unsupported file format detected.
(103ac9ce-8feb-4d0b-95a2-18b5f2b61b7a.blend)”

A .blend file is obviously a Blender file, but this 3MF does not contain any .blend files. The only possibility I can think of is that some metadata inside the file says the STL originated from Blender, but I have no idea why that should matter. Blender is one of the largest 3D modeling programs in existence. What is the plan here, to ban Blender from being used?

Here is my workflow:

I have a normal Blender file. I export STL files from Blender. I import those STLs into Bambu Studio. I slice and configure the file in Bambu Studio, then save it as a 3MF. There is no .blend file anywhere in the final 3MF from what we can see. It appears to only be metadata, if anything.

Repairing or fixing the model does not change the error.

The most frustrating part is that this exact same file uploaded to MakerWorld just two weeks ago. It passed with no issue. I only wanted to separate one of the plates into its own profile, so I deleted the other plate and tried to re-upload it. Suddenly, it fails.

Even more confusing: I took the same original file, saved it as something else, deleted the main plate instead, and uploaded that as a new profile. That one worked fine. So one plate uploads, but the other plate does not, even though both came from the same original file and the same workflow.

There is no rhyme or reason.

I have tried redoing the entire file with freshly exported and imported STLs. It still fails. Saving the 3MF under a new name does nothing. It still fails.

I have a few more ideas to test, and I am not giving up, but this is beyond frustrating. Between this, the unknown prime tower parameter issue where custom parameters are no longer accepted, beta files being blocked instead of simply removing unsupported features for older versions, and being unable to change something as simple as a title, description, or photo on an existing model because MakerWorld re-verifies the already-uploaded file against newer validation rules even though the file itself was never changed, it is becoming ridiculous.

It feels like every update adds another unexplained restriction or bug that makes the creator experience worse.

[Cypherous]

Its because you have a .blend file also uploaded, if you click the “download STL/CAD” its showing a .blend file which was probably added as an additional file when you originally uploaded it

[Virtality]

The .blend file shown under “Download STL/CAD Files” is attached to the main model post as the CAD/source file. MakerWorld lists .blend as a supported CAD/source file type, which is why it was accepted there in the first place.

The problem I’m running into is with a print profile. The 3MF files are uploaded through the profiles, while the CAD/source file is tied to the main model post. I am not changing or replacing that main source file.

What makes it more confusing is that I was able to upload a brand-new profile for this same model recently, while another profile/edit fails with this .blend error. If the main post’s .blend file was the actual blocker, I would expect all profile uploads for this model to fail consistently, or for MakerWorld to clearly flag the source file itself.

So while the listing does have a .blend source file, that alone does not explain why one profile works and another fails when the 3MF being uploaded does not contain a .blend file.

[Virtality]

New attempt: I exported all of the parts from Bambu Studio back out as STLs, then imported those STLs into a completely fresh 3MF file and tried uploading again. Same failure.

I also unpacked the 3MF as a ZIP and searched both the extracted file names and the contents of the text-based files inside it. There is no .blend file, no .blend reference, no Blender reference, and no matching UUID inside the profile 3MF.

So at this point, the profile 3MF appears clean. The error is still claiming an unsupported .blend file exists, but nothing in the actual uploaded 3MF supports that.

That makes this look much more like a MakerWorld validation bug, cached server-side reference, or some other internal validation issue rather than an actual unsupported file inside the print profile.

[Cypherous]

And what if you just delete the .blend file you uploaded? each profile does reference those files afaik

[Virtality]

The issue with that theory is that it does not match what actually happened.

In the same timeframe, one profile upload failed with the .blend error, while another new profile upload on the same model succeeded. If every profile truly references the main post’s .blend source file in a way that blocks validation, then both profile uploads should have failed.

I understand that the main post has a .blend source file attached, but that file was accepted by MakerWorld as a supported CAD/source file. The 3MF I am uploading for the profile does not contain a .blend file or even a .blend reference after unpacking and searching it.

[Cypherous]

Ok, but did you try it to see if thats the issue, because going round in circles saying you aren’t uploading a blend file doesn’t really matter if its the previously uploaded one that is the issue

[Virtality]

I get what you are suggesting, but that does not fit this. I do really appreciate the thoughts and ideas.

This is not a case where I originally uploaded a profile containing a .blend file, then changed something later. The profile that passed two weeks ago was the same file. No .blend file was inside that 3MF then, and no .blend file is inside it now.

I even downloaded the already-approved profile file directly from MakerWorld, split the two plates into separate profiles, and tried uploading them separately. One plate/profile uploaded successfully. The other failed with the .blend error.

That is the part your explanation does not account for.

If the main post’s source file was the actual blocker, then both new profile uploads should have failed because they are attached to the same main model post. If the profile 3MF itself was the issue, then the original profile would not have passed two weeks ago, and the unpacked 3MF should contain a .blend file or reference. It does not.

So I understand deleting the source file could be a troubleshooting test, but it would not explain the inconsistency. The problem is that MakerWorld is returning a .blend error for a profile 3MF that does not contain a .blend, while another profile on the same model passes.

[Cypherous]

Thats still a lot of words to not answer the question, did you do the troubleshooting step of deleting it, if deleting it solves the issue then you just open a support ticket and your job is done, the timeline doesn’t really matter, all that matters is “does x stop y from working”

[Virtality]

Yes, deleting the source file or nuking the entire post and rebuilding it would fix the issue.

I already filed a support ticket. This post is not asking whether there is a problem. We know there is a problem. The point is to rule out every other possibility and figure out why MakerWorld is re-checking the main STL/CAD source file when editing a print profile.

At this point, yes, it is clearly tied to the CAD/source file somehow.

A helpful test I just ran was uploading more new profiles using the same file that fails on edit. The new profiles pass the 3MF validation and post successfully. But editing that same profile minutes later, even just changing the title, fails because MakerWorld checks the main post CAD/source file. That should not be happening when the profile 3MF contains no .blend file or .blend reference.

I am not removing a valid source file from a live listing while MakerWorld is failing validation on edits, because I clearly will not be able to add it back.

A useful test would be something like this: if another user uploads a profile to my post, can they edit it afterward, or are they locked out too?

“Just delete it” is not useful.

[Cypherous]

Thing is the profile always includes any source CAD files you uploaded as they have to be available if someone selects the profile and then hits the option to download the CAD files, geometry isn’t supposed to change between profiles so the assumption is the .blend file would still be the same as the model so gets dragged along for the ride

So one of two things has happened, they either no longer actually want .blend files to be included and just haven’t updated the list of allowed files or someone made an edit to the code and removed it from the list of supported file types which is now causing it to fail

[Virtality]

That is a fair point. I did not think about it from the user end.

Given they are completely separate on the creator side, it is not obvious that profile edits would touch the main CAD/source file at all.

It is still an incredibly stupid implementation. I can upload brand-new profiles and they will all pass, but I can’t edit that same profile minutes later without it failing because of the main post CAD file.

And if they really did drop .blend support and remove the ability to edit anything tied to it, then how do they explain leaving the old models up? It is a double-edged sword. You cannot have it both ways.

If .blend is not allowed to be associated with a model anymore, then why are all the models with .blend files still up and the world is still somehow spinning?

If this is the future, that means anyone in this situation has to completely redo their CAD/source files for any minor change because MakerWorld decided it is fine to leave the file there, but not fine to touch it.

Stupid.

[Cypherous]

Which is why i’m more inclined to think it was the latter, and that someone borked an update somewhere, so it just sees the file and assumes its unsupported so won’t let you create the new profile but its not built to delete the old one so leaves it alone

I would wait and see what the support rep tells you once they answer your ticket

[Virtality]

Unfortunately, I have too many people waiting on a model update tied to this, so I can’t just sit on it and wait (gave them over 24h). If removing the .blend source file is what gets the profiles working again, then that is what I have to do.

[Cypherous]

Yeah its going to take longer than 24 hours given the timezones and the fact that its a weekend