Pulish Web App Error

manuelmrtz

While trying to publish a Web App, I get the following error,

I tried different included project examples and got the same result.

I don't get errors when I click Run.

Manny

Garry

Hi Manny. Thanks for the report, and welcome to the forums!

That error code (0x8007000B) is Windows refusing to load a file because its format doesn't match what it expected - the classic "damaged or mismatched binary" error rather than a problem with your projects. Since Run works fine and every Web project fails identically, this points at something on your computer: most often a corrupted installation or security software having interfered with Studio's files.

To get to the bottom of it, could you:

Share the full error. Your screenshot crops the message to one line. After the failure, Studio shows a "Publish failed during …" message at the bottom of the window and a panel with the complete error entry - a screenshot of the whole Studio window after a failed publish would tell me exactly which stage is failing.
Confirm your setup. Which Studio version you're using (from the About dialog) plus your Windows version and "System type" from Settings → System → About. In particular, let me know if this is a Windows on ARM machine (e.g. Snapdragon-powered).
Try publishing a Desktop example. Open one of the bundled desktop example projects and choose Publish. Desktop packaging takes a different path than Web - if that succeeds (or fails with a different error), it narrows this down considerably.
Reinstall from a fresh download. Grab the installer from objo.dev again and reinstall. While you're at it, check whether your antivirus flagged or quarantined anything during the original install - that produces exactly this kind of damage.

The fact that Run works is genuinely useful: it tells me the compiler, runtime and host executables on your machine are all healthy, so whatever is failing is specific to the packaging stage. If it still misbehaves after a fresh install, post those details here and we'll keep digging until it's sorted.

manuelmrtz

When I Publish the first time, this is the error.

If I try to publish again for the second and consecutive times, this is the error.

I removed and reinstalled this version.

My system setup.

I have published Desktop Apps for Windows and Linux without issues.

Manny

Garry

Hi Manny - your follow-up cracked it. Thank you, and apologies for the reinstall runaround: this was Objo's bug, not anything on your computer.

I can confirm that publishing Web apps from Studio on Linux fails in 26.10.1 with exactly the errors in your screenshots, and I've reproduced it on a completely clean Linux install of Studio, so nothing on your system needs fixing.

The desktop publishes you ran were the key clue. When Studio publishes a Web app as a single executable, it uses a helper library from the .NET SDK for the final packaging step, and Studio carries its own copy of that helper. The copy included in the Linux build turns out not to be loadable on Linux: the SDK compiles that library separately for each operating system and architecture, and we were unknowingly shipping the macOS flavour inside the Linux build. That one defect explains everything you saw:

Run works, because running doesn't do the single-file packaging.
Desktop publishing works, because it takes a different packaging path that never touches this library.
Web publishing fails on the first attempt with the long "Could not load file or assembly 'Microsoft.NET.HostModel…'" message, and on later attempts with the shorter "incorrect format (0x8007000B)" - the same failure surfacing two different ways.

The fix is done for the next release (https://feedback.objo.dev/bug/1678. Studio will now build that helper from source directly into the app, so it is identical on every platform. I've verified Linux Web publishing end to end with the fix, including starting the published app, and it will be in the next release. If you need to get a web app deployed before then, reply and we'll sort out a path for your setup in the meantime.