stuck on "Host is loading project..."

Lately I’ve been experiencing that preview is stuck on “Host is loading project…”.

This for instance:

With this command: fuse preview BundleImageList.unoproj

Same here when trying to preview just the default code after creating a new project.

Fuse version 0.11.0 (build 6183)

Uno version 0.26.9-OSX (build 1951)

Thanks for reporting this. We will investigate Tuesday

Been reporting that as well. the examples still seem to work, but on a personal project that happens almost all the time.

adb disconnect adb connect 192.168.1.*:5555

It’s not necessarily Android related. Happens with Local Preview as well.

When I ctrl+c a stuck preview I get this, although I think it’s not really useful:

Build completed in 7.51 seconds.
    0 Warning(s)
    0 Error(s)
Build ended
GL_VERSION: 2.1 INTEL-10.14.58
GL_VENDOR: Intel Inc.
GL_RENDERER: Intel Iris Pro OpenGL Engine
System.OperationCanceledException: The operation was canceled.
  at System.Threading.CancellationToken.ThrowOperationCanceledException () [0x00000] in <filename unknown>:0 
  at System.Threading.CancellationToken.ThrowIfCancellationRequested () [0x00000] in <filename unknown>:0 
  at System.Threading.ManualResetEventSlim.Wait (Int32 millisecondsTimeout, CancellationToken cancellationToken) [0x00000] in <filename unknown>:0 
  at System.Threading.Tasks.Task.SpinThenBlockingWait (Int32 millisecondsTimeout, CancellationToken cancellationToken) [0x00000] in <filename unknown>:0 
  at System.Threading.Tasks.Task.InternalWait (Int32 millisecondsTimeout, CancellationToken cancellationToken) [0x00000] in <filename unknown>:0 
  at System.Threading.Tasks.Task.Wait (Int32 millisecondsTimeout, CancellationToken cancellationToken) [0x00000] in <filename unknown>:0 
  at System.Threading.Tasks.Task.Wait (CancellationToken cancellationToken) [0x00000] in <filename unknown>:0 
  at Outracks.Fusion.Native.DisplayLinkView.Draw () [0x00000] in /Users/outracks/buildAgent1/work/b939dc4c6ac331f9/Source/Outracks.Fusion.Native-OSX/DisplayLinkView.cs:90 
CoreAnimation: warning, deleted thread with uncommitted CATransaction; set CA_DEBUG_TRANSACTIONS=1 in environment to log backtraces.

Hi guys,

Bolav, I am unable to reproduce the problem with the project you linked.

The rest of you experiencing this problem, can you please help debugging by typing

fuse host-preview

in the project folder. This should give a more detailed error message for this kind of error.


Building project...

Starting simulator...
Simulator running, endpoints:

Press Ctrl+C to shut down

And that’s it. Nothing else happens.

Cbereveanu: Can you provide your test case please? You can PM it to me on slack if you don’t want to share it all.

Edit: We now have a reproducing test case and will debug asap.

For those doing fuse host-preview as mentioned above, the full command you need is fuse host-preview --compile-only YourProject.unoproj.

Note that if this command succeeds, it will output the bytecode of your project, which you might not want to post here. You can just remove everything in the Dumping stringified bytecode block of the output before pasting.

Update: apparently I had messed up the unoproj file (ux file inclusion missing), but the fact is that the “Host is loading project” problem was occuring back when I had only “*" in the included files section. After adding ".ux:UX” to the includes, the fuse host-preview compiles without errors, but the problem remains: preview stuck at “Host is loading project”.

Hi Costin, I just wanted to let you know that I’ve reproduced the problem with your project, even after fixing the .unoproj. We’ve made a top priority ticket to investigate this. We’ll keep you posted here as soon as we know more.



Pinpointed the issue to the video tag. An app with the following content would hang in that state. The video file in question used to load properly on older builds.

<App Theme="Basic">
        <Page ux:Class="PageWithVideo" ux:Name="self" HitTestMode="LocalBoundsAndChildren">
            <DockLayout />
            <PageWithVideo Color="#FFF">
                    <Video File="Assets/Video/intro.mp4" IsLooping="true" StretchMode="UniformToFill" Layer="Background" Volume="0.0" AutoPlay="true" />
        <BottomBarBackground />

Even more specific, the app blocks if AutoPlay is present. Without it, the video preview shows fine.


Thanks for you help debugging this issue. I found a bug in <Video> that could cause Preview to hang on loading project, the fix will be included in the upcoming release :slight_smile:

:smiley: great! Glad to be of assistance.