Windows 7 took forever to load if you had a solid background. Now we know why

Windows 7, launched in 2009, marked a significant turnaround for Microsoft following the mixed reception of Windows Vista. However, even this celebrated operating system was not immune to peculiar glitches, one of which has recently resurfaced in discussions among tech enthusiasts.

In a detailed blog post, Microsoft veteran Raymond Chen shed light on an intriguing issue that plagued some users: a delay of 30 seconds during the boot process when a single-color image was set as the desktop background. This seemingly minor aesthetic choice had unexpected consequences for the operating system’s performance.

Chen explained that the root of the problem lay in a programming oversight. Upon logging in, Windows 7 would sequentially load various desktop components—such as the taskbar, application icons, and the background image. The system was designed to wait for confirmation from each component before proceeding. However, if a user opted for a single-color background, the necessary feedback message indicating that the background was ready never materialized. Consequently, the system defaulted to a 30-second fallback, delaying access to the desktop.

The crux of the issue: The code responsible for signaling that the background image was ready was embedded within the bitmap code of the image itself. Since a single color does not qualify as a bitmap, the system was left in limbo, waiting in vain for a message that would never arrive.

This delay could also manifest if users enabled the “Hide desktop icons” group policy. This feature was introduced after the main code was written, leading to further complications as Windows 7 initially failed to recognize the policy’s implications, thereby prolonging the loading time.

// Original code
InitialiseDesktopIcons()
{
    bind to the desktop folder
    enumerate the icons
    add them to the screen
    Report(DesktopIconsReady);
}

// Updated with group policy support

InitialiseDesktopIcons()
{
    if (desktop icons allowed by policy)
    { 
        bind to the desktop folder
        enumerate the icons
        add them to the screen
        Report(DesktopIconsReady);
    } 
}

Unsolved for months

Chen noted that it took several months for Microsoft to identify and rectify this issue. By November 2009, an update was released to address the problem, ensuring that users could enjoy a smoother experience without the unwelcome delay. This anecdote serves as a reminder of the complexities and unexpected challenges that can arise in software development.

Further reading: How a Janet Jackson song crashed laptops for 9 years

This article was originally featured in our sister publication PC-WELT and has been translated and localized from German.