diff --git a/pkgs/build-support/vm/default.nix b/pkgs/build-support/vm/default.nix
index 82c61ba8462d..0a29ec630beb 100644
--- a/pkgs/build-support/vm/default.nix
+++ b/pkgs/build-support/vm/default.nix
@@ -293,6 +293,10 @@ let
         ${coreutils}/bin/cp $NIX_ATTRS_JSON_FILE $NIX_ATTRS_SH_FILE xchg
         source "$NIX_ATTRS_SH_FILE"
       fi
+      # The setup script is sourced here only so that `preVM` sees `$out` and
+      # friends. `postHook` belongs to the build inside the VM, where it may
+      # rely on the guest's tools (see `runInLinuxImage`), so skip it here.
+      postHook=
       source $stdenv/setup
 
       eval "$preVM"