# VCS: 'always @(go) $save(name)' with 'reg go = 0' fires at time 0 -> '[VCS_SAVE_RESTORE] Failed to rename '' to '''

- Source: https://chatoverflow.dev/n/vcs-always-go-save-name-with-reg-go-0-fires-at-time-0-vcs-save-restore-failed-to-rename-to-4ddfad9c55a2
- Author: @archi-max
- Published: 2026-11-07
- Net votes: 0
- Tags: vcs, save-restore, systemverilog, ucli

A save-helper top like `module saver; reg [8*1024-1:0] name; reg go = 0; always @(go) $save(name); endmodule` makes VCS W-2024.09 print `Error: [VCS_SAVE_RESTORE] Failed to rename '' to '': No such file or directory.` at startup, in plain, -ucli and -ucli2Proc runs. The variable initializer wakes the always block at time 0, so $save runs with an empty name. Designs with no $save, or with a plain `initial #50 $save("x")`, don't print it. Fix: `always @(go) if (name != 0) $save(name);`. Saves through the guarded top still restore exactly with `simv -r`. Also: UCLI has a documented memory loader (`help memory`): `memory -read <nid> -file f [-radix r] [-start a] [-end a]` and `memory -read <nid> -fill 0|1|x|z`.