Are you on 2.91? I admit I haven’t used multires much lately, but I remember having this issue twice; the first time it was because I hadn’t applied the transformations on the mesh. The second time I forgot to remove a subsurf modifier before adding multires, and that broke everything. 
Maybe that’s the case for you as well? A mesh with non-uniform scale or any other modifier before multires?
Pablo Dobarro mentioned using sculptgl code when the work on multires started, here’s what Brecht said about it:
Here’s the thing about MultiRes. It is only halfway done. The devs completed about half of the tasks needed for MultiRes last year, so until that happens we will be stuck with what we have. I really hope they finish it this year, since I don’t think it is wise to wait with completing such an essential part of the sculpting workflow.
Agree, there’s still a lot of work to do with multires to be considered production-ready, I just wanted to point out that sculptgl was brought up at the beginning as a possible solution.
I personally hope that performance and sculpt layers (or shapekeys for multires) get a priority, on top of taking care of those nasty “mesh destroying” bugs, of course.
Correct and fast C and C++ is needed not some javascript bloat so it is not just copy paste. Thanks to fast code and no-bloat is one thing that makes Blender so insanely fast even on laptops.
I moved some vertices a bit forward around the head area after enabling MR because they were hard to
shape in the sculpt mode but that is pretty much it, no topology change in the edit mode.
The interesting thing is that making those changes did not break it right away, at least I kept sculpting another 10 mins without issues, including increasing and decreasing the subd res along the way. This happened when I added a new material to the model.
Bear in mind that I had similar issues even when I never put the model into the edit mode. I am just suspecting that there are multiple edge cases that are propagating this issue, just that I am so far not clear about the exact nature of steps to reprocude these.
In some cases I had no issues with nudging verts in edit mode and MR did not break. I think these kinds of breakages does not happen right away, rather it reveals the issue somewhat many minutes after whatever rubs the MR modifier the wrong way.
Zbrush resolves this issue by asking you to freeze the subdividision, then it lets you use certain tools like Zmodeler. Maybe Blender devs can put such bandaid until this is fully resolved.
This was 2.92 alpha.
It looks like I bumped the model accidentally, however not sure if I did that before or after MR
That would be great if you could narrow it down…!
BF needs to hire someone to implement a proper multi-level system solely for sculpting…
and another 1,2 or more to give a hand to pablo :D…
Yeah, someone else working on the sculpting area would be great… the basic stuff needs a lot of love… 
Should we send the node setup to bake VDM to Pablo? I’ve been testing it with the default blender in cycles and it works, and he said that it was the main reason to not implement vector displacement brushes.
Edit: just in case somebody want to try it, you have to bake that as emit texture, and to see it you have to enable in the material >settings >surface > displacement and to use the node tree below.
Edit 2: I don’t know where to report this really but if somebody can and want to feel free to do it. :^)
I use this graph to bake VDM out of marvelous designer models, so i can use these maps with the displace modifier, on the flat/UVed mesh
Sergey was working on this, but his time has recently been taken up by sequencer work.
Numerous issues with Multires will likely be resolved once the patches from Joseph Eager (and the other optimization patches) are in master. The pieces to really bring sculpting to a seriously powerful tool are there, we just need to convince the devs to start giving more priority to what I would call the ‘usability patches’.
How fast it will happen I don’t know, Blender has a ton of areas where usability lacks in one or more ways, the polish work alone would be months of full time work even for 20 devs.
Multires still creates spikes in some weird, random, hard-to-reproduce cases. It’s definitely less bad now that 5 years ago. So I really appreciate the efforts of Sergey and other devs to solve and improve it because it’s a crucial modifier for sculpting.
For me the worst part is waiting for Vertex Colors support for Multires. Pablo Dobarro made a patch but seems to me it’s not happening anytime soon…
It is simmilar to the one I posted and 'll try to do more test but your setup isn’t giving me acurate results in the displace modifier and doesn’t work in the render as VDM, should the VDM bake be reported as non documented somewhere?
Sorry, I’ve been off this topic for quite some time.
Just wanted to know if there’s a chance or if it’s already been worked on having a faster voxel remesher?
Thanks
Is it running super slow there? 
I’m still using an old i7 2600k and voxel remeshing to ~1 million faces takes around 5 to 10 seconds. I think that is quite fast.
Would it be possible to only ( voxel ) remesh parts of a model?
For example:
You have a character and you would like to add extra detail only in the face.
So you would only have remesh the face, while the rest can stay on another lower detail level.
The advantage would be that the polycount is lower then if the whole model is remeshed.
Maybe also the remeshing itself can be faster as there is less that’s need to be remeshed.
T73047 Sculpt Mode Multires Design (blender.org)
