You can find the up to date information on this page:

There have been so many updates and everyone is in different stages of migration so it’s been a nightmare to consolidate information. It’s best to browse from the world-building section to find what you need.

I’ve noticed that a few of my problems get stuck when generating a 2020.3.9 build for the first time switching from 2019 and it can be a very scary moment when you realise that box isn’t going to ever complete.

You are in the middle of a migration, there are glitches and uncertainty about upgrading your worlds and this becoming a more problematic issue that I am running into more and more. But thankfully, I have found a workaround and I have tested this on projects that I was willing to lose (backed up however) so that I could try and show how you can work around this.


I started using Unity for the first time a few months ago. However, I have a profound technical understanding of technology and am very good at reverse engineering concepts to better understand them. You should seek advice from the AltSpace discord. I also would objectively tell people that I may be making crucial mistakes that may work in this example by luck but may be considered a ‘hacky unstable approach’.

Backup before editing your worlds

You should always back up your projects, but if you have exhausted all other options and you have waited long enough, and now you are at the point where you need to shut down your computer, read on.

  • If you are in mid-upgrading and you didn’t back up your files beforehand. First of all, why? But I would recommend copying the files that you can, although some may be stuck in memory and cannot be copied.

GI Data is cache that will get written to your files

When light is generating, your computer calculates the lighting from different points of view and passes over objects differently and at different diffuses. This gets generated in cache and then written to disk to write your lightmaps, shaders and textures etc.

So in terms of “catastrophic” consequences, the worse thing that will most likely happen is that you will have an incompleted render of your world.

What happens if the GI data is cancelled/stopped or forced-stopped

Since it’s cache files, the most likely scenario is that you will have partially baked worlds if you forcefully quit Unity and reopen. This is a positive sign because if your world has retained information in the cache to build, it will have a higher degree of completing successfully if you build and upload the second time.

  • My only conclusion is that sometimes the merging can get stuck and sometimes gets stuck in a loop, and the program doesn’t know how to retry or skip. So sometimes it can work itself out, but sometimes it can’t.
  • Re-generating your lighting and reuploading should tell Unity to sort itself out and generate what it hasn’t generated and in my experience is that this issue can be fixed just by turning off auto-generate lighting and manually generating your world and uploading.

My research into this issue

This Reddit article was the top result on Google but I also was able to read about it elsewhere on the internet. After turning off auto-generate lighting it appeared to fix the loop.

Kiling your project safely

If you have the ability to cancel the GI data build or build process itself press the cancel button.

If your Build GI data has been building for 21 seconds and you are ready to exit out of Unity. It would be safe to say you are being impaitent. If however your world has been stuck in this state for hours and hours you can press the cancel button.

Your project may proceed to the next steps of generating the world. If you can’t cancel the process because the box is frozen you will need to open up task manager and kill the program forcefully if you cannot shut it down.

End the task and wait for Unity to fully close. it may give you a bug error issue.

Fixing the GI Data Part2

Opening up after cancelling the process would be a scary thought but I allowed the cache to regenerate and made sure I unticked auto-generate lighting and then generated my lighting again. This solved my problem.

I was able to build and complete this world


Something to do with jumping from Unity 2019 > 2020 and using the AltSpaceVR uploader breaks the auto-generate lighting feature. This feature seems to create a feedback loop that prevents projects from ever fully rendering and being uploaded to AltSpaceVR.