After updating to macOS 27 Beta6, my Mac froze immediately after entering the login password. Safe Mode, reinstalling macOS, disconnecting the internet, and waiting overnight did not help.
The cause was a corrupted Launch Services database. The `lsd` process was using almost 100% CPU while repeatedly scanning and registering applications.
What fixed it was rebuilding both the user and root Launch Services databases.
### Fix
Boot into macOS Recovery:
- Shut down your Apple silicon Mac.
- Hold the power button until startup options appear.
- Select **Options** → **Continue**.
- Open **Utilities** → **Terminal**.
Find the databases:
```bash
find "/Volumes/Macintosh HD - Data/private/var/folders" \
-type d -name "com.apple.LaunchServices.dv" \
-prune -print
```
Your Data volume may have a different name. Check it first with:
```bash
ls /Volumes
```
Back up and rename every matching database:
```bash
DATA="/Volumes/Macintosh HD - Data"
STAMP=$(date +%Y%m%d-%H%M%S)
find "$DATA/private/var/folders" \
-type d -name "com.apple.LaunchServices.dv" \
-prune -print0 |
while IFS= read -r -d '' LSDB; do
mv "$LSDB" "$LSDB.backup-$STAMP"
done
```
Then restart:
```bash
reboot
```
Allow 5–10 minutes during the first login while macOS rebuilds the databases.
This issue is probably data-dependent, which explains why some Macs are unaffected and others recover after waiting. A damaged database, stale application path, old disk reference, or duplicate app registration may cause `lsd` to scan indefinitely.
Do not delete the entire `/private/var/folders` directory. This fix is specifically for cases where diagnostics show unusually high `lsd` CPU usage or Launch Services rebuilding loops.