Symptoms
In a Parallels Remote Application Server environment, administrators may observe that Connection Brokers, Enrollment Servers, or Remote PC Agents intermittently transition to a "Not Verified" state in the RAS Console.
The issue may present with the following behavior:
- Intermittent status changes
Agent status fluctuates between OK, Not Verified, and Reboot Required without any configuration changes. - Persistent recovery failure
Restarting RAS services or rebooting the server does not permanently resolve the issue. -
Installation failure
Manual reinstallation of the Agent MSI fails with the error: "Cannot install because UDP port is in use."
Cause
This behavior is typically caused by environmental conditions, rather than a defect in the Parallels RAS product.
Common contributing factors include:
- Interference during service startup
Antivirus scans, backup scripts, or other third-party processes may interfere with the service initialization sequence.
This can result in a state where the service is reported as running by Windows but remains unresponsive to the RAS Controller. - Resource or timing constraints
On systems with limited resources, RAS services may fail to initialize correctly during system startup, especially if required dependencies (such as network services) are not yet fully available. - External service manipulation
Security software or administrative scripts that stop or restart services may leave the agent in a state where it cannot automatically return to a Verified status.
Resolution
1. Upgrade to the latest RAS version
Upgrade your environment to Parallels RAS 21.1.1 (build 26679) or later.
This version introduces the RAS Watchdog Service, which monitors RAS components and automatically recovers services that become unresponsive or stop unexpectedly.
2. Configure RAS Watchdog settings
The Watchdog behavior is controlled via the Windows Registry.
Navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Parallels\Watchdog
Adjust the Watchdog-related values according to your environment requirements:
|
Value |
Type |
Recommended Value |
Description |
|
InitialTimeToWait |
REG_DWORD |
|
Delay (in msec) before the watchdog begins checking services after a reboot.
|
|
KeepMonitoring |
REG_DWORD |
|
Set to
|
|
TimeInterval |
REG_DWORD |
|
Frequency (in msec) of the service health checks.
|
|
QuarantineTime |
REG_DWORD |
|
If a service restarts 3 times within this window, the watchdog stops attempts until a manual start occurs.
|
3. Configure antivirus exclusions
To prevent the issue from occurring, exclude Parallels RAS components from real-time antivirus scanning.
At minimum, exclude:
- Parallels RAS installation directory
- RAS service executables
- Related working directories (logs, temp files)
Important: Antivirus interference is one of the most common causes of service startup deadlocks.
Additional Notes
- The Watchdog Service provides automatic recovery, but it does not eliminate the root cause if external interference persists.
- For highly constrained environments, consider reviewing system startup order and service dependencies.
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