Fix: Snap.prompting-client High CPU Usage

Nov 13, 2025 by Alex Johnson 42 views

**Fix: snap.prompting-client.daemon.service Constantly Restarts and Consumes 100% CPU**

Experiencing high CPU usage and constant restarts of snap.prompting-client.daemon.service can be frustrating. This article delves into a specific scenario where this issue occurs on Ubuntu 25.04 when the graphical session is not logged in, offering insights and potential solutions. We'll explore the problem, analyze the logs, and discuss possible causes and remedies to get your system running smoothly again.

Understanding the Issue

The core problem revolves around the snap.prompting-client.daemon.service, a component related to the snapd daemon. Snapd is a service that manages snap packages, which are containerized software packages that are designed to be secure and easy to install. The snap.prompting-client.daemon.service appears to be involved in prompting the user for some kind of action, but when a graphical session isn't active, it enters a problematic loop, consuming excessive CPU resources and restarting frequently. The observed behavior suggests a dependency on the graphical environment, which, when absent, triggers the instability. When logging in to a desktop install via ssh, while the graphical session is not logged in, I noticed that snapd is consuming 100% cpu from time to time and snap.prompting-client.daemon.service is constantly restarting. After logging in the graphical session, the crash restart loop stops, which suggests the problem is related to a missing graphical session.

Analyzing System Information

To effectively troubleshoot, it's crucial to gather relevant system information. Here's a breakdown of the provided data:

Operating System: Ubuntu 25.04
Snapd Version: 2.68.5+ubuntu25.04.2 (with a candidate version of 2.72+ubuntu25.04 available)

These details offer a starting point for identifying potential compatibility issues or known bugs associated with the specific versions of Ubuntu and snapd in use. The availability of a newer snapd version (2.72+ubuntu25.04) hints at the possibility that upgrading might resolve the issue, as newer versions often include bug fixes and performance improvements. It's important to note the phased update rollout (20%), suggesting a cautious approach to the update process, likely to mitigate potential widespread issues.

Examining the Logs

Log analysis provides valuable clues about the nature of the problem. The journalctl output reveals a repeating pattern:

The service starts.
It logs that it's using the snapd snap socket at /run/snapd-snap.socket.
It quickly restarts.

This cycle continues indefinitely until a graphical session is established. After logging into the graphical session, the logs show the service starting and then attempting to remove an old socket file (/run/user/1000/snap.prompting-client/prompting.sock). The error message "No such file or directory" indicates that the socket file might not always be present, which could be a consequence of the repeated restarts. The logs also show the service checking for pending prompts and finding none, suggesting that the core functionality of the service might not be essential when no prompts are pending. These observations indicate a potential race condition or a failure to handle the absence of a graphical environment gracefully.

Possible Causes and Solutions

Based on the analysis, several potential causes could be contributing to the issue:

Dependency on Graphical Environment: The service might have an implicit or explicit dependency on the graphical environment, causing it to fail when no session is active. Solution: Investigate the service's configuration to determine if it can be disabled or configured to run differently when no graphical session is present.
Bug in Snapd or the Prompting Client: A bug in either snapd or the prompting client itself could be causing the restart loop. Solution: Upgrade snapd to the latest available version (2.72+ubuntu25.04 in this case) and monitor if the issue persists. Also, check for updates to the prompting-client snap.
Socket File Issues: The service's attempt to remove an old socket file might be related to the problem. Solution: Ensure that the service has the necessary permissions to create and remove socket files in the specified directory. Also, investigate why the socket file might be missing in the first place.
Resource Contention: When no graphical session is active, the system might be under different resource constraints, leading to the service's failure. Solution: Monitor system resource usage (CPU, memory, I/O) when the issue occurs to identify potential bottlenecks.

Steps to Resolve the Issue

Here's a step-by-step approach to address the problem:

Update Snapd:
```
sudo apt update
sudo apt upgrade snapd
```
This will update snapd to the latest available version.
Disable the Service (if possible):

If the snap.prompting-client.daemon.service is not essential, try disabling it:
```
systemctl --user disable snap.prompting-client.daemon.service
```
This will prevent the service from starting automatically. You can also stop the service:
```
systemctl --user stop snap.prompting-client.daemon.service
```
Investigate Service Configuration:

Examine the service's configuration file to identify any dependencies on the graphical environment. The configuration file is usually found at /usr/lib/systemd/user/snap.prompting-client.daemon.service or /etc/systemd/user/snap.prompting-client.daemon.service. Look for directives like Requires, Wants, or After that might indicate dependencies.
Check Socket File Permissions:

Ensure that the service has the necessary permissions to create and remove socket files in the /run/user/1000/snap.prompting-client/ directory. You can check the permissions using:
```
ls -l /run/user/1000/snap.prompting-client/
```
If necessary, adjust the permissions using chmod or chown.
Monitor System Resources:

Use tools like top, htop, or vmstat to monitor system resource usage when the issue occurs. This can help identify potential bottlenecks or resource contention.
Report the Bug:

If none of the above steps resolve the issue, consider reporting the bug to the Ubuntu or snapd developers. Provide detailed information about your system, the steps you've taken, and the logs you've collected.

Further Troubleshooting

If the above steps don't fully resolve the issue, consider these additional troubleshooting steps:

Examine Snapd Logs: Check the main snapd logs for any related errors or warnings. These logs are typically located at /var/log/syslog or /var/log/daemon.log.
Reinstall the Snap: Try reinstalling the prompting-client snap to ensure that all files are intact and correctly configured.
Check for AppArmor Issues: AppArmor is a security system that can restrict the capabilities of applications. Check if AppArmor is preventing the snap.prompting-client.daemon.service from accessing necessary resources.

Conclusion

The snap.prompting-client.daemon.service consuming 100% CPU and constantly restarting is a complex issue that requires careful investigation. By analyzing system information, examining logs, and systematically applying potential solutions, you can identify the root cause and restore your system's stability. Remember to report any unresolved issues to the relevant developers to contribute to the overall improvement of Ubuntu and snapd. This comprehensive approach should help you diagnose and resolve the problem effectively.

For more information on troubleshooting snapd issues, visit the Snapcraft documentation at the Snapcraft website. This resource provides valuable insights and guidance on managing snap packages and resolving common problems.