Failed executing external process for 'Clustering' job - error when light baking

I have a scene in which I'm trying to bake the lights for. When I try to set up my light bake - it takes FOREVER, way longer than normal to the point which i end up canceling it but while baking i keep seeing this error pop up:
Failed executing external process for 'Clustering' job.

any thoughts on whats causing it? or how to fix it?

Im using Unity 5.3.4 f1 on a macbook pro

 

Same here - any ideas?

 

1. Try latest unity version
2. Clean GI Cache and restart unity
3. Set ~100gb free space on hard drive with full access permission for GI Cache

 

Found out how to fix the issue as I couldn't find a solution online. What I could guess is that it had to do with cache being shared between different versions of unity or attempting to launch another versions baking process.

So, what I did was uninstalled all unity things from my computer (not including the projects I am working on), and then downloaded the hub first. Then downloaded the oldest unity version into its own custom folder (such as "Unity 2017.4") and set the custom location to that folder. Opened it up, test the bake and if it worked, then make a new separate folder for the next newest unity version. So on and so forth.

Keep the versions separate and make sure you set the hubs installations to each unities .exe launcher since this issue seems to be based on LTS versions of unity.

 

Having the same issue on 2021 LTS.
This has been going on since Unity 5.

Unity has failed to provide a permanent solution.

 

Can confirm - this has been an ongoing issue for years now. I really hope that one day, it will just work, and we can spend more time on our games, than on trying to figure out WHY Unity won't work / breaks on lightmap baking.