I have tried to load particle data of subhaloes for TNG50-1 but it takes forever . It has worked for lower resolutions(TNG100-2, TNG300-2) . I'm running in my laptop with 8GB RAM and I'm not sure is it either having a memory crash or some other issue. I have downloaded all the files for snapshot 99.
Maybe try TNG50-3 for testing, and to check all is working well?
If you are loading particles for one subhalo, this should still generally work on your laptop. Make sure to specify fields as only those you need. Note that the first few subhalos/halos are very, very large, and this won't be possible (e.g. subhalo 0). But once you get to halo 100 or so, there shouldn't be any problem.
Thank you. I checked subhaloes in TNG50-1 for subhaloes over 10. Some loads and still there are few don't load. I guess probably limitations with my small RAM.
For other simulations including TNG300-3,300-2 all the subhaloes load