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    :Troubleshoot Drive C disk space loss on a Windows instance

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    :Troubleshoot Drive C disk space loss on a Windows instance

    Last Updated:Apr 15, 2026

    Identify and resolve common causes of Drive C disk space loss on a Windows ECS instance.

    Symptom

    Drive C on a Windows ECS instance is running out of space, causing the operating system to malfunction.

    Quick reference

    Click a cause to jump to its solution.

    Cause

    Key indicator

    Recommended solution

    System logs

    Large files in C:\Windows\Logs\CBS

    Run DISM.exe /Online /Cleanup-Image /SPSuperseded

    Temporary files

    Large files in C:\windows\temp or %USERPROFILE%\AppData\Local\Temp

    Run del /S /Q %TEMP%\*

    Windows system updates

    Large C:\windows\WinSxS directory

    Run DISM.exe /Online /Cleanup-Image /StartComponentCleanup

    Virtual memory allocation

    Virtual memory configured on Drive C

    Reconfigure virtual memory settings

    Before you begin

    Back up important data on Drive C before performing any cleanup to prevent accidental data loss.

    Cause 1: System logs consume excessive disk space

    Windows stores logs from Windows Update, DISM repairs, and other system operations in C:\Windows\Logs\CBS. Without regular cleanup, these logs can consume significant disk space.

    Solution

    Use one of the following methods to free up disk space consumed by system logs.

    Method 1: Use DISM.exe to clean up log files

    Run the following command in an elevated Command Prompt to clean up obsolete log files:

    DISM.exe /Online /Cleanup-Image /SPSuperseded

    Method 2: Manually delete system log files

    Important

    Back up system log files before manual deletion. Improper deletion may cause system instability.

    Cause 2: Temporary files consume excessive disk space

    Windows creates temporary files during OS and application operations, typically stored in C:\windows\temp or %USERPROFILE%\AppData\Local\Temp.

    Solution

    Use one of the following methods to free up disk space consumed by temporary files.

    Method 1: Run a command to delete temporary files

    Run the following command in an elevated Command Prompt:

    del /S /Q %TEMP%\*

    Method 2: Manually delete temporary files

    Navigate to C:\windows\temp or %USERPROFILE%\AppData\Local\Temp and delete unneeded temporary files.

    Cause 3: Windows system updates consume excessive disk space

    Windows downloads updates and patches to C:\windows\WinSxS and backs up old versions. Without cleanup, these files accumulate and consume excessive disk space.

    Important

    Do not manually delete files in the WinSxS folder. Doing so may damage your system, prevent booting, or break applications.

    Solution

    Use one of the following methods to free up disk space consumed by Windows updates.

    Method 1: Use DISM.exe to clean up the WinSxS folder

    Run the following command in an elevated Command Prompt to clean up obsolete Windows Update files:

    DISM.exe /Online /Cleanup-Image /StartComponentCleanup

    Method 2: Use the Disk Cleanup tool

    Use the Disk Cleanup tool to clean up Drive C.

    Cause 4: Virtual memory consumes Drive C disk space

    When physical memory is insufficient, Windows uses disk space as virtual memory. If virtual memory is configured on Drive C, the pagefile reduces the available disk space.

    Solution

    Verify the virtual memory configuration and adjust if needed. How do I configure the virtual memory of a Windows instance?

    References

    Use tools such as WinDirStat and SpaceSniffer to analyze disk usage, identify large directories, and drill down into specific files.