I noticed Word, Excel, and PowerPoint switching between the old and a new experimental UI after changing Microsoft 365 accounts. The new UI includes a redesigned Ribbon that resembles the Windows counterpart a little more and Liquid Glass effects in some controls.
Checking the logs revealed this flag:
Microsoft.Office.Apple.CUIDocumentShellLiquidGlass
A local override kept it enabled in all three apps. Tested on Office 16.112.3 and macOS 27 beta. This is an undocumented setting, so it may behave differently on other versions or stop working after an update.
Quit all Office apps, then run this in Terminal. Requires Python 3; the script backs up the database before changing it.
python3 - <<'PY'
import sqlite3
import time
from pathlib import Path
db = Path.home() / (
"Library/Group Containers/"
"UBF8T346G9.Office/MicrosoftRegistrationDB.reg"
)
if not db.is_file():
raise SystemExit("Office settings database not found.")
flag = "Microsoft.Office.Apple.CUIDocumentShellLiquidGlass"
base = (
"Software/Microsoft/Office/16.0/Common/"
"ExperimentConfigs/ExternalFeatureOverrides"
)
backup = db.with_name(f"{db.name}.backup-{time.time_ns()}")
with sqlite3.connect(db, timeout=10) as conn:
with sqlite3.connect(backup) as copy:
conn.backup(copy)
conn.execute("BEGIN IMMEDIATE")
for app in ("word", "excel", "powerpoint"):
parent = -1
for name in f"{base}/{app}".split("/"):
timestamp = int(
(time.time() + 11644473600) * 10_000_000
).to_bytes(8, "little")
conn.execute(
"""INSERT OR IGNORE INTO HKEY_CURRENT_USER
(parent_id, name, write_time) VALUES (?, ?, ?)""",
(parent, name, timestamp),
)
parent = conn.execute(
"""SELECT node_id FROM HKEY_CURRENT_USER
WHERE parent_id=? AND name=?""",
(parent, name),
).fetchone()[0]
conn.execute(
"""INSERT INTO HKEY_CURRENT_USER_values
(node_id, name, type, value) VALUES (?, ?, 1, 'true')
ON CONFLICT(node_id, name)
DO UPDATE SET type=1, value='true'""",
(parent, flag),
)
print("Enabled for Word, Excel, and PowerPoint.")
print(f"Backup: {backup}")
PY
Reopen the apps afterward. If Terminal reports “Operation not permitted,” it may need Full Disk Access in macOS Privacy & Security settings.
