Trouble shooting
Annoying issues will be noted here.
World Locking issues
Low frame rate
World Locking Tools should have no discernable impact on your framerate. (An exception is that the visualizations will eventually drag down your framerate after many anchors have been created, but the visualizers are just for diagnostics, not for shipping with your application.)
If you see a framerate drop after adding World Locking Tools to your application, check your Unity logs. That usually means an exception is being repeatedly generated.
Missing dll's etc.
This has been seen from the Frozen World Engine dll. Go to NuGet for Unity:
NuGet > Manage NuGet Packages > Installed
uninstall and re-install the latest FrozenWorld.Engine package. See NuGet Setup.
Alternately, install using the MR Feature Tool and have dependencies installation handled for you.
Missing 'FrozenWorld' namespace
Errors like the following (usually a lot):
Assets\WorldLocking.Engine\Plugin.cs(10,37): error CS0234: The type or namespace name 'FrozenWorld' does not exist in the namespace 'Microsoft.MixedReality' (are you missing an assembly reference?)
It is missing the FrozenWorld.Engine DLL. See NuGet Setup.
Alternately, install using the MR Feature Tool and have dependencies installation handled for you.
It's not working
Check the Unity logs for errors and exceptions.
Check that your scene camera is attached to at least one other object. See the setup in WorldLocking.Examples.WorldLockingPhysicsSample for example. If you are doing dynamic camera manipulation, you may need to keep the WorldLockingManager informed of the current camera. See World
More general Unity/AR problems
"DirectoryNotFoundException: Could not find a part of the path"
The path has grown too long. See fuller explanation here.
"A remote operation is taking longer than expected" message box then failure to deploy
Check your USB connection. A bad cable, a bad port, missing IPOverUSB, can all cause this. But it's probably somewhere on the communication path from your PC to your device.
Missing Windows SDK components
Mismatch between Visual Studio version indicated in Unity versus Visual Studio version you're trying to build with. Check:
Unity > File > Build Settings > Visual Studio Version
Especially dangerous is if that's set to Latest Installed and you have multiple versions of Visual Studio installed.
On HoloLens, application starts up as a slate, rather than an AR experience
If targeting the Unity's built-in VR support, also known as Legacy XR, then check:
Unity > Project Settings > Player > XR Settings
You must have Virtual Reality Supported checked, and the Windows Mixed Reality in Virtual Reality SDKs.
If using Unity's AR Subsystems / XR SDK, then check that you've followed all the steps here. Likely culprits are missing one of the required packages, or if using MRTK, that the appropriate profile has not been setup on the MixedRealityToolkit object.
When building for ARM on HoloLens2, app stops at startup. ARM64 works fine
The fix is either disable Graphics Jobs under
Project Settings > Player > Other Settings > Graphics Jobs
or just build for ARM64.