diff --git a/install.sh b/install.sh
index f7d4baa19c..d90195399d 100755
--- a/install.sh
+++ b/install.sh
@@ -718,8 +718,20 @@ _smart_apt_install() {
                     exit 1
                     ;;
             esac
-            sudo apt-get update -y </dev/null
-            sudo apt-get install -y $_STILL_MISSING </dev/null
+            # Mirror the headless branch: on a sudoers denial, a wrong password
+            # or an apt error, say what to run by hand instead of letting set -e
+            # abort on a bare sudo/apt message.
+            if sudo apt-get update -y </dev/null &&
+                sudo apt-get install -y $_STILL_MISSING </dev/null; then
+                :
+            else
+                echo ""
+                echo "    Could not install these packages: $_STILL_MISSING"
+                echo "    See the error above."
+                echo "    Please install them first, then re-run Unsloth Studio setup:"
+                echo "    sudo apt-get update -y && sudo apt-get install -y $_STILL_MISSING"
+                exit 1
+            fi
         else
             # Nobody can answer a prompt or type a password here. -n makes sudo
             # refuse rather than prompt into a closed stdin, which is how #7307
@@ -4091,9 +4103,11 @@ echo ""
 # In non-interactive environments (Docker, CI, cloud-init) just print instructions.
 if [ "$_SKIP_AUTOSTART" != true ] && [ -t 1 ]; then
     echo ""
-    printf "  Start Unsloth Studio now? [Y/n] "
     # No readable answer (closed/EOF tty) defaults to no; Enter is still yes.
-    if [ -r /dev/tty ]; then
+    # Prompt only when something can answer: `test -r` passes on the unopenable
+    # /dev/tty found in containers, leaving a dangling question in the log.
+    if _can_read_tty; then
+        printf "  Start Unsloth Studio now? [Y/n] "
         read -r _reply </dev/tty || _reply="n"
     else
         _reply="n"
diff --git a/studio/setup.sh b/studio/setup.sh
index 5c393b9fbf..b4088c15b6 100755
--- a/studio/setup.sh
+++ b/studio/setup.sh
@@ -67,6 +67,15 @@ fi
 step()    { printf "  ${C_DIM}%-15.15s${C_RST}${3:-$C_OK}%s${C_RST}\n" "$1" "$2"; }
 substep() { printf "  %-15s${2:-$C_DIM}%s${C_RST}\n" "" "$1"; }
 
+# ── Helper: can the controlling terminal actually be opened for reading? ──
+# `test -r` only checks permission bits, which look fine in containers and
+# systemd units where open() then fails with ENXIO. Probe with a real open.
+# Mirrors install.sh's _can_read_tty; defined here too because setup.sh runs
+# as its own process (install.sh invokes it, it does not source it).
+_can_read_tty() {
+    ( : </dev/tty ) >/dev/null 2>&1
+}
+
 _is_verbose() {
     [ "${UNSLOTH_VERBOSE:-0}" = "1" ]
 }
@@ -1510,25 +1519,46 @@ if [ "$_NEED_LLAMA_SOURCE_BUILD" = true ] && grep -qi microsoft /proc/version 2>
         step "gguf deps" "installed"
     elif command -v sudo >/dev/null 2>&1; then
         step "gguf deps" "sudo required for: $_STILL_MISSING" "$C_WARN"
-        printf "  %-15s" ""
-        printf "accept? [Y/n] "
-        if [ -r /dev/tty ]; then
-            read -r REPLY </dev/tty || REPLY="y"
+        if _can_read_tty; then
+            printf "  %-15s" ""
+            printf "accept? [Y/n] "
+            # The device opened, so a failed read is EOF, not consent: decline.
+            read -r REPLY </dev/tty || REPLY="n"
+            case "$REPLY" in
+                [nN]*)
+                    substep "skipped -- run manually:"
+                    substep "sudo apt-get install -y $_STILL_MISSING"
+                    _SKIP_GGUF_BUILD=true
+                    ;;
+                *)
+                    # Degrade like the no-sudo branch below rather than letting
+                    # set -e abort setup on a bare apt error: missing GGUF build
+                    # deps are recoverable, not fatal.
+                    if sudo apt-get update -y </dev/null &&
+                        sudo apt-get install -y $_STILL_MISSING </dev/null; then
+                        step "gguf deps" "installed"
+                    else
+                        step "gguf deps" "install failed -- run manually:" "$C_WARN"
+                        substep "sudo apt-get update -y && sudo apt-get install -y $_STILL_MISSING"
+                        _SKIP_GGUF_BUILD=true
+                    fi
+                    ;;
+            esac
         else
-            REPLY="y"
-        fi
-        case "$REPLY" in
-            [nN]*)
-                substep "skipped -- run manually:"
-                substep "sudo apt-get install -y $_STILL_MISSING"
+            # Nobody can answer a prompt or type a password here, so -n makes
+            # sudo refuse rather than prompt into a closed stdin, and -k ignores
+            # any cached timestamp so only a real NOPASSWD rule gets through.
+            # Same treatment as install.sh's _smart_apt_install. This is the WSL
+            # GGUF-export case noted above, where sudo does want a password.
+            if sudo -n -k apt-get update -y </dev/null &&
+                sudo -n -k apt-get install -y $_STILL_MISSING </dev/null; then
+                step "gguf deps" "installed (non-interactive sudo)"
+            else
+                step "gguf deps" "needs sudo, no terminal -- run manually:" "$C_WARN"
+                substep "sudo apt-get update -y && sudo apt-get install -y $_STILL_MISSING"
                 _SKIP_GGUF_BUILD=true
-                ;;
-            *)
-                sudo apt-get update -y
-                sudo apt-get install -y $_STILL_MISSING
-                step "gguf deps" "installed"
-                ;;
-        esac
+            fi
+        fi
     else
         step "gguf deps" "missing (no sudo) -- install manually:" "$C_WARN"
         substep "apt-get install -y $_STILL_MISSING"
diff --git a/tests/sh/test_apt_distro_prompt.sh b/tests/sh/test_apt_distro_prompt.sh
index 6c3d08198f..62033fa4c5 100755
--- a/tests/sh/test_apt_distro_prompt.sh
+++ b/tests/sh/test_apt_distro_prompt.sh
@@ -163,6 +163,11 @@ run_smart() {
                     *) return 1 ;;
                 esac
             fi
+            # Sudoers refuses the command outright, with or without -n.
+            if [ "$_sudo_mode" = denied ]; then
+                echo "sudo: user is not allowed to execute that" >&2
+                return 1
+            fi
             echo "SUDO_RAN: $*"
         }
         # shellcheck disable=SC1090
@@ -199,6 +204,13 @@ _out=$(run_smart tty needspasswd)
 assert_contains "tty present: still prompts" "$_out" "Accept? [Y/n]"
 assert_contains "tty present: accepts and installs" "$_out" "SUDO_RAN: apt-get install -y cmake"
 
+# Consent given at a real tty, but the elevated apt-get fails anyway (sudoers
+# denial, wrong password, apt error). The interactive branch must say what to
+# run by hand, like the headless branch does, not die on the bare sudo error.
+_out=$(run_smart tty denied)
+assert_contains "tty + denied sudo: gives the manual command" \
+    "$_out" "sudo apt-get update -y && sudo apt-get install -y cmake"
+
 # No sudo at all keeps its own message.
 _out=$(run_smart notty absent)
 assert_contains "no sudo binary: unchanged message" "$_out" "sudo is not available on this system"