Glad to hear --cores=1 helped! I have seen some strange behavior in x86_64 qemu VMs, but also --cores=1 did help me build rust-1.54 bootstrap on x86_64. It also might be a bug in guix-daemon, perhaps only in the old 1.4.0 revision, judging from how the error message says store protocol error.
I will close this bug and not investigate further, but if you want to investigate, you could try if, after upgrading your system with `guix system reconfigure`, the command guix build --check --no-grafts /gnu/store/6cmb5svslbgrhmbg6mkh40x5rnzfvqsg-graphviz-minimal-7.0.1.drv continues to fail and maybe file a more specific bug that the graphviz-minimal package must specify that it can be built on one core only. That is ‘#:parallel-build?’ ‘#:parallel-tests?’ might have to be false. At least if someone can observe this outside a VM. On my four core riscv Visionfive2, `guix build --check --no-grafts graphviz-minimal` succeeds, though. Regards, Florian
