Failed to start tailwatchd - Unit tailwatchd service entered failed state

The error Failed to start tailwatchd - Unit tailwatchd.service entered failed state means the cPanel log monitoring daemon could not start. Tailwatchd monitors log files for events like failed logins (cPHulk), Eximstats email processing, and other cPanel services.

/scripts/restartsrv_tailwatchd
# If that fails:
killall tailwatchd 2>/dev/null
/usr/local/cpanel/libexec/tailwatchd
systemctl start tailwatchd

01. Diagnose the Issue

# Check the service status
systemctl status tailwatchd

# Check for error details
journalctl -u tailwatchd --no-pager -n 50

# Check if the PID file is stale
ls -la /var/run/tailwatchd.pid
cat /var/run/tailwatchd.pid
ps -p $(cat /var/run/tailwatchd.pid 2>/dev/null) 2>/dev/null

02. Common Fixes

Stale PID File

The most common cause. Tailwatchd crashed but the PID file was not cleaned up:

rm -f /var/run/tailwatchd.pid
/scripts/restartsrv_tailwatchd

Corrupted Log File

If tailwatchd fails because it cannot parse a log file it is watching:

# Check which logs it monitors
cat /etc/tailwatchd.conf

# Rotate problematic logs
/scripts/cpanel_log_rotation

Memory/Resource Exhaustion

If the server is low on memory, tailwatchd may fail to start:

free -m
# If swap is full, kill memory hogs first
ps aux --sort=-%mem | head -10

cPanel Binary Corruption

/scripts/check_cpanel_rpms --fix
/scripts/upcp --force

Quick Recap

1. Check status: systemctl status tailwatchd
2. Remove stale PID: rm -f /var/run/tailwatchd.pid
3. Restart: /scripts/restartsrv_tailwatchd
4. If corrupt: /scripts/check_cpanel_rpms --fix
5. Check memory if the server is under resource pressure

5,440 users found this article useful · Last updated March 2026 · Browse all Server Maintenance articles