# [RDD_PID_FILE_LOCK](https://apps.juniper.net/syslog-explorer/?msg=RDD_PID_FILE_LOCK)

## SYSLOG Details
- **Message**: Unable to lock PID file (<variable>error-message</variable>)
- **Help**: rdd could not lock PID file
- **Description**: The redundant interfaces process (rdd) attempted to lock the file that records its process ID (PID), which serves to prevent multiple instances of rdd from running simultaneously. The attempt failed.
- **Type**: SNO: Should Not Occur
- **Severity**: error
- **Cause**: -
- **Action**: -
- **Attributes**: error-message
- **Facility**: LOG_DAEMON

## Found this message in the following releases:
- [Junos OS 24.2R1](https://apps.juniper.net/syslog-explorer/?msg=RDD_PID_FILE_LOCK&sw=Junos%20OS&rel=24.2R1)
- [Junos OS 23.4R1](https://apps.juniper.net/syslog-explorer/?msg=RDD_PID_FILE_LOCK&sw=Junos%20OS&rel=23.4R1)