diff --git a/install.sh b/install.sh
index b3eaa61003..548e6f702a 100755
--- a/install.sh
+++ b/install.sh
@@ -447,8 +447,12 @@ _on_install_exit() {
     if [ "$_status" -ne 0 ]; then
         _restore_studio_venv_replacement
     fi
+    [ -n "${_UV_OVERRIDE_TMPDIR:-}" ] && rm -rf "$_UV_OVERRIDE_TMPDIR" 2>/dev/null || true
     exit "$_status"
 }
+# Empty so an inherited value can never reach the trap's rm; only a temp dir
+# this script creates below (Apple Silicon, spaced path) is ever removed.
+_UV_OVERRIDE_TMPDIR=""
 trap _on_install_exit EXIT
 
 # ── Helper: download a URL to a file (supports curl and wget) ──
@@ -1427,6 +1431,25 @@ fi
 if [ "$OS" = "macos" ] && [ "$_ARCH" = "arm64" ]; then
     _OVERRIDES_FILE="$(cd "$(dirname "$0" 2>/dev/null || echo ".")" && pwd)/studio/backend/requirements/single-env/overrides-darwin-arm64.txt"
     if [ -f "$_OVERRIDES_FILE" ]; then
+        # uv splits UV_OVERRIDE on whitespace, so a repo path with whitespace
+        # truncates it and aborts every later uv call (issue #6503). Hand uv a copy.
+        case "$_OVERRIDES_FILE" in
+            *[[:space:]]*)
+                _UV_OVERRIDE_TMPDIR=$(mktemp -d 2>/dev/null) || _UV_OVERRIDE_TMPDIR=""
+                case "$_UV_OVERRIDE_TMPDIR" in
+                    "") ;;
+                    *[[:space:]]*) rm -rf "$_UV_OVERRIDE_TMPDIR" 2>/dev/null || true; _UV_OVERRIDE_TMPDIR="" ;;
+                    *)
+                        if cp "$_OVERRIDES_FILE" "$_UV_OVERRIDE_TMPDIR/overrides-darwin-arm64.txt" 2>/dev/null; then
+                            _OVERRIDES_FILE="$_UV_OVERRIDE_TMPDIR/overrides-darwin-arm64.txt"
+                        else
+                            rm -rf "$_UV_OVERRIDE_TMPDIR" 2>/dev/null || true
+                            _UV_OVERRIDE_TMPDIR=""
+                        fi
+                        ;;
+                esac
+                ;;
+        esac
         export UV_OVERRIDE="$_OVERRIDES_FILE"
     fi
 fi
diff --git a/tests/python/test_install_uv_override_space.py b/tests/python/test_install_uv_override_space.py
new file mode 100644
index 0000000000..86d918b043
--- /dev/null
+++ b/tests/python/test_install_uv_override_space.py
@@ -0,0 +1,31 @@
+"""Run the install.sh UV_OVERRIDE space-safety shell test (issue #6503) under
+pytest, so the auto-discovered CPU test job executes it. The dedicated
+`Shell installer tests` CI job runs a fixed script list that this is not part
+of, so without this wrapper the regression would only be covered locally via
+tests/run_all.sh.
+"""
+
+from __future__ import annotations
+
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+SHELL_TEST = REPO_ROOT / "tests" / "sh" / "test_install_uv_override_space.sh"
+
+
+@pytest.mark.skipif(sys.platform == "win32", reason = "POSIX shell installer test")
+@pytest.mark.skipif(shutil.which("bash") is None, reason = "bash not available")
+def test_install_uv_override_space_shell():
+    assert SHELL_TEST.is_file(), f"missing shell test: {SHELL_TEST}"
+    proc = subprocess.run(
+        ["bash", str(SHELL_TEST)],
+        capture_output = True,
+        text = True,
+    )
+    assert proc.returncode == 0, proc.stdout + proc.stderr
+    assert "ALL PASSED" in proc.stdout, proc.stdout + proc.stderr
diff --git a/tests/run_all.sh b/tests/run_all.sh
index 18182d9db7..d03f4c4d4f 100755
--- a/tests/run_all.sh
+++ b/tests/run_all.sh
@@ -15,6 +15,7 @@ sh "$TESTS_DIR/sh/test_resolve_cuda_archs.sh"
 sh "$TESTS_DIR/sh/test_strixhalo_wsl_reroute.sh"
 sh "$TESTS_DIR/sh/test_uninstall_shared_icon.sh"
 sh "$TESTS_DIR/sh/test_torch_flavor.sh"
+sh "$TESTS_DIR/sh/test_install_uv_override_space.sh"
 
 echo ""
 echo "=== Python tests ==="
diff --git a/tests/sh/test_install_uv_override_space.sh b/tests/sh/test_install_uv_override_space.sh
new file mode 100755
index 0000000000..07ef36295a
--- /dev/null
+++ b/tests/sh/test_install_uv_override_space.sh
@@ -0,0 +1,112 @@
+#!/bin/bash
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
+# uv splits UV_OVERRIDE on whitespace, so a repo cloned under a path with a space
+# truncates it and aborts every later uv call (issue #6503). install.sh must hand
+# uv a space-free copy. Exercises the real install.sh hardening block.
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+INSTALL_SH="$SCRIPT_DIR/../../install.sh"
+PASS=0
+FAIL=0
+
+ok()  { echo "  PASS: $1"; PASS=$((PASS + 1)); }
+bad() { echo "  FAIL: $1"; FAIL=$((FAIL + 1)); }
+
+# Extract the UV_OVERRIDE hardening block (outer case ... esac plus the export)
+# and run it directly, so the test tracks install.sh rather than a copy of it.
+BLOCK=$(awk '
+    /case "[$]_OVERRIDES_FILE" in/ { grab = 1 }
+    grab { print }
+    grab && /export UV_OVERRIDE="[$]_OVERRIDES_FILE"/ { exit }
+' "$INSTALL_SH")
+if ! printf '%s' "$BLOCK" | grep -q 'export UV_OVERRIDE'; then
+    echo "  FAIL: could not extract UV_OVERRIDE block from install.sh"
+    exit 1
+fi
+
+run_block() {
+    _OVERRIDES_FILE="$1"
+    _UV_OVERRIDE_TMPDIR=""
+    unset UV_OVERRIDE
+    eval "$BLOCK"
+}
+
+echo "=== test_install_uv_override_space ==="
+
+# 1. Spaced path -> space-free copy with identical contents, temp dir tracked.
+WORK=$(mktemp -d)
+mkdir -p "$WORK/Open Source"
+SRC="$WORK/Open Source/overrides-darwin-arm64.txt"
+printf 'transformers>=4.57.6\n' > "$SRC"
+run_block "$SRC"
+case "$UV_OVERRIDE" in
+    *[[:space:]]*) bad "spaced path: UV_OVERRIDE still contains whitespace ($UV_OVERRIDE)" ;;
+    *)             ok  "spaced path: UV_OVERRIDE is whitespace-free" ;;
+esac
+[ "$UV_OVERRIDE" != "$SRC" ] && ok "spaced path: points at a copy" || bad "spaced path: not copied"
+[ "$(cat "$UV_OVERRIDE" 2>/dev/null)" = "transformers>=4.57.6" ] \
+    && ok "spaced path: copy contents identical" || bad "spaced path: contents differ"
+{ [ -n "$_UV_OVERRIDE_TMPDIR" ] && [ -d "$_UV_OVERRIDE_TMPDIR" ]; } \
+    && ok "spaced path: temp dir tracked for cleanup" || bad "spaced path: temp dir not tracked"
+# The exit-trap cleanup (_on_install_exit) must then remove it.
+[ -n "$_UV_OVERRIDE_TMPDIR" ] && rm -rf "$_UV_OVERRIDE_TMPDIR" 2>/dev/null || true
+[ ! -d "$_UV_OVERRIDE_TMPDIR" ] && ok "spaced path: temp dir removable" || bad "spaced path: temp dir lingers"
+rm -rf "$WORK"
+
+# 2. No-space path -> passthrough, no temp dir.
+PLAIN=$(mktemp -d)
+PSRC="$PLAIN/overrides-darwin-arm64.txt"
+printf 'transformers>=4.57.6\n' > "$PSRC"
+run_block "$PSRC"
+[ "$UV_OVERRIDE" = "$PSRC" ] && ok "no-space path: UV_OVERRIDE unchanged" || bad "no-space path: changed ($UV_OVERRIDE)"
+[ -z "$_UV_OVERRIDE_TMPDIR" ] && ok "no-space path: no temp dir created" || bad "no-space path: temp dir created"
+rm -rf "$PLAIN"
+
+# 3. TMPDIR itself contains a space -> fall back to the original path, no leak.
+WORK2=$(mktemp -d)
+mkdir -p "$WORK2/Open Source" "$WORK2/tmp dir"
+SRC2="$WORK2/Open Source/overrides-darwin-arm64.txt"
+printf 'transformers>=4.57.6\n' > "$SRC2"
+RES=$( TMPDIR="$WORK2/tmp dir"; export TMPDIR; run_block "$SRC2"
+       printf 'UV_OVERRIDE=%s\nTMPDIR_VAR=%s\n' "$UV_OVERRIDE" "$_UV_OVERRIDE_TMPDIR" )
+echo "$RES" | grep -qx "UV_OVERRIDE=$SRC2" \
+    && ok "spaced TMPDIR: falls back to original path" || bad "spaced TMPDIR: did not fall back ($RES)"
+echo "$RES" | grep -qx "TMPDIR_VAR=" \
+    && ok "spaced TMPDIR: no temp dir tracked" || bad "spaced TMPDIR: temp dir tracked"
+# mktemp may have created a dir under the spaced TMPDIR; it must not be leaked.
+_leftover=$(find "$WORK2/tmp dir" -mindepth 1 -maxdepth 1 -type d 2>/dev/null | head -n1)
+[ -z "$_leftover" ] && ok "spaced TMPDIR: no leaked temp dir" || bad "spaced TMPDIR: leaked $_leftover"
+rm -rf "$WORK2"
+
+# 4. A tab in the path is whitespace uv also splits on -> copied like a space.
+WORK3=$(mktemp -d)
+TABDIR=$(printf 'Open\tSource')
+mkdir -p "$WORK3/$TABDIR"
+SRC3="$WORK3/$TABDIR/overrides-darwin-arm64.txt"
+printf 'transformers>=4.57.6\n' > "$SRC3"
+run_block "$SRC3"
+case "$UV_OVERRIDE" in
+    *[[:space:]]*) bad "tab path: UV_OVERRIDE still contains whitespace" ;;
+    *)             ok  "tab path: UV_OVERRIDE is whitespace-free" ;;
+esac
+[ -n "$_UV_OVERRIDE_TMPDIR" ] && rm -rf "$_UV_OVERRIDE_TMPDIR" 2>/dev/null || true
+rm -rf "$WORK3"
+
+# 5. install.sh must clear _UV_OVERRIDE_TMPDIR before registering the exit trap,
+# so an inherited value can never reach the trap's rm -rf.
+_init_line=$(grep -n '^_UV_OVERRIDE_TMPDIR=""' "$INSTALL_SH" | head -n1 | cut -d: -f1)
+_trap_line=$(grep -n '^trap _on_install_exit EXIT' "$INSTALL_SH" | head -n1 | cut -d: -f1)
+{ [ -n "$_init_line" ] && [ -n "$_trap_line" ] && [ "$_init_line" -lt "$_trap_line" ]; } \
+    && ok "init: _UV_OVERRIDE_TMPDIR cleared before exit trap" \
+    || bad "init: _UV_OVERRIDE_TMPDIR not cleared before exit trap (init=$_init_line trap=$_trap_line)"
+
+echo ""
+echo "  PASS: $PASS"
+echo "  FAIL: $FAIL"
+if [ "$FAIL" -gt 0 ]; then
+    echo "FAILED"
+    exit 1
+fi
+echo "ALL PASSED"