This is what I get after cancelling a rustup toolchain remove:
PS C:\Users\Jonas\Documents\breeze-emu> rustup toolchain remove nightly-i686-pc-windows-msvc
info: uninstalling toolchain 'nightly-i686-pc-windows-msvc'
error: could not remove update hash file: 'C:\Users\Jonas\.multirust\update-hashes\nightly-i686-pc-windows-msvc' (Das System kann die angegebene Datei nicht finden. (os error 2))
PS C:\Users\Jonas\Documents\breeze-emu>
EDIT: And a rustup update ... gives:
PS C:\Users\Jonas\Documents\breeze-emu> rustup update nightly-i686-pc-windows-msvc
info: syncing channel updates for 'nightly-i686-pc-windows-msvc'
info: downloading component 'rustc'
36.42 MiB / 36.42 MiB (100.00%) 1004.80 KiB/s ETA: 0s
info: downloading component 'rust-std'
48.12 MiB / 48.12 MiB (100.00%) 1.07 MiB/s ETA: 0s
info: downloading component 'rust-docs'
5.57 MiB / 5.57 MiB (100.00%) 1.55 MiB/s ETA: 0s
info: downloading component 'cargo'
2.40 MiB / 2.40 MiB (100.00%) 1.06 MiB/s ETA: 0s
info: installing component 'rustc'
info: rolling back changes
error: failed to install component: 'rustc-i686-pc-windows-msvc', detected conflict: '"share/doc/rust/LICENSE-APACHE"'