**System Information**
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1660 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.89
**Blender Version**
Broken: version: 2.91.2, branch: master, commit date: 2021-01-19 16:15, hash: `rB5be9ef417703`
Tried with 2.83LTS
blender 2.93.0 ae1e68f5146d
Worked: None
**Short description of error**
Was working in Sculpt mode, tried to hide the arms and the program crashed.
I tried with another objects with multires and it doesn't happen
Here the .Blend with the problem
{F9598264}
**Exact steps for others to reproduce the error**
Go to Sculpt Mode -> Try to mask with mask brush, Mask Lasso or Mask Box