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Failed to log in to a Windows CVM due to high CPU and memory usage

Last updated: 2022-04-06 20:30:24

    This document describes how to troubleshoot Windows CVM login failures due to high CPU or memory utilization.

    The following uses Windows Server 2012 R2 as an example. The steps may vary by operating system (OS) versions.

    Possible Causes

    Hardware, system processes, service processes, trojans, and viruses may cause high CPU or memory utilization, resulting in slow service response speed or CVM login failure. You can use Cloud Monitor to create an alarm threshold for CPU or memory usage. You will be notified promptly when the configured threshold is exceeded.


    1. Identify the process that causes high CPU or memory utilization.
    2. Analyze the process.
    • If it is an unhealthy process, it may be caused by a virus or trojan. Terminate the process or use an antivirus application to scan the system.
    • If it is a service process, check whether the high CPU or memory utilization is caused by access traffic and whether it can be optimized.
    • If it is a Tencent Cloud component process, submit a ticket for assistance.


    Task Manager: an application and process manager included with the Microsoft Windows OS. It provides information on computer performance and running software, such as the names of running processes, CPU load, memory usage, I/O, logged-in users, and Windows services.

    • Processes: a list of all running processes.
    • Performance: system performance statistics such as the overall CPU usage and current memory usage.
    • Users: all users with sessions.
    • Details: an enhanced version of the processes tab, including detailed information on PID, status, CPU usage, and memory usage.
    • Services: a list of all services, including those that are not running.

    Troubleshooting Method

    Logging in to the CVM instance using VNC

    If you cannot log in to your CVM instance due to high CPU or memory utilization, we recommend logging into Windows instance via VNC.

    1. Log in to the CVM console.
    2. On the instance management page, locate the CVM instance and click Log In, as shown in the following figure:
    3. In the pop-up "Log into Windows instance" window, select Alternative login methods (VNC) and click Log In Now to log in to the CVM instance.
    4. In the pop-up login window, select "Send CtrlAltDel" in the upper-left corner and click Ctrl-Alt-Delete to go to the OS login page, as shown in the following figure:

    Viewing the resource usage of processes

    1. In the CVM, right-click the "taskbar" and choose Task Manager, as shown in the following figure:
    2. View resource usage in the "Task Manager" window, as shown in the following figure:

      You can click the CPU or memory column to sort the processes in ascending or descending order.

    Analyzing processes

    Analyze processes in Task Manager to identify the causes and troubleshoot accordingly.

    A system process causes the issue

    If a system process causes high CPU and memory utilization, troubleshoot as follows:

    1. Check the name of the process.
      Some viruses use names similar to system processes, such as svch0st.exe, explore.exe, iexplorer.exe, etc.
    2. Check the location of the executable file of a process.
      The executable file of a system process is usually located in C:\Windows\System32 with valid signatures and descriptions. To locate the executable file of a process, such as svchost.exe, right-click the process in Task Manager and choose Open file location.
    • If the executable file is not in C:\Windows\System32, your CVM instance may have a virus. Scan for viruses with an antivirus application or manually fix the issue.
    • If the executable file is in C:\Windows\System32, restart your CVM instance or terminate unnecessary but secure system processes.

    The following lists common system processes:

    • System Idle Process: a process that displays the percentage of time that the processor is idle
    • system: indicates the memory management process
    • explorer: indicates the desktop and file management process
    • iexplore: indicates the Microsoft Internet Explorer process
    • csrss: indicates the runtime subsystem on the Microsoft client or server
    • svchost: indicates the system process for running DLL
    • Taskmgr: indicates the task manager
    • Isass: indicates the local security authority service

    An unhealthy process causes the issue

    If high CPU or memory utilization is caused by a process that has a strange name, such as xmr64.exe (a cryptomining malware), your CVM instance may have a virus or trojan. We recommend using a search engine to verify.

    • If the process is a virus or trojan, use an antivirus application to delete the virus or trojan. If necessary, back up your data and reinstall the operating system.
    • If the process is not a virus or trojan, restart your CVM instance or terminate unnecessary but secure processes.

    A service process causes the issue

    If a service process such as IIS, HTTPD, PHP, or Java causes the issue, we recommend analyzing it further.
    For example, check whether your business volume is high.

    • If yes, we recommend upgrading configuration for your CVM instance. Alternatively, you can optimize service processes.
    • If no, use service error logs to further analyze the issue. For example, check whether incorrect parameter configurations lead to resource waste.

    A Tencent Cloud process causes the issue

    • If a Tencent Cloud component process causes the issue, submit a ticket to contact us for assistance.
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