Can't Edit Cached Particles I must be misunderstanding something because for the life of me I can't seem to get the editing of a cached particle system with Hair Dynamics to work. I tried in 2.83 and 2.9, but in both all the hairs disappear, the cache becomes totally corrupted and I have to delete/recreate a new one for the hairs to show back up, a whole new cache, not just delete the bake.
Just from a basic cube, add hair particle, check Hair Dynamics, scroll down to cache, set end frame to 20, Bake, save, scroll to frame 20, go to Particle Edit, Particles disappear and cache is corrupted. If I close and reopen the without saving the hairs are still gone (which is why I assume cache is getting corrupted).
Disk Cache is NOT checked, but maybe there is some other cache parameters I am missing? Or maybe it is a plugin? I have many, though I can't easily turn them all off.
https://docs.blender.org/manual/en/latest/physics/particles/mode.html
Here is an example blend file, if I tab into particle editor at this point the hairs get destroyed. Do others get this too? Am I missing a step?
https://drive.google.com/file/d/1Q9lAERudg_qia51_wVxeyVqj9v7B1MpB/view?usp=sharing
Thanks, I have spent, oh let's see, about 12 hours now straight fiddling with this damned thing.
There is a reported bug In Particle Edit mode, Emitter particles are not visible in the viewport. It is about Emitter particles, but Hair particles are not visible either in Blender 2.91.
As a workaround you can

bake/run the simulation
convert the desired frame to a Mesh object in the modifier's panel
use the add-on Hairnet 0.6.3 (for Blender 2.9.1) to generate a new Hair Particle System based on the mesh data

Hairnet will edit the particles and place them along the mesh edges. Use the button 'Fibremesh'. Select the mesh first, then the scalp/head (must be highlighted light orange). The script may run a while depending on the number of particles.