When you start a Windows Vista-based computer, you may receive a "Stop 0x50" error message that resembles the following: This problem typically occurs very early in the startup process. For example, the problem may occur shortly after the splash screen appears, and you see a black screen with a moving progress bar. Specifically, this problem typically occurs when the system tries to load the i8042prt.sys driver. The problem only occurs in certain hardware configurations.

Back to the top

Service pack information

To resolve this problem, obtain the latest service pack for Windows Vista. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Back to the top

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista, x86-based versions

File name	File version	File size	Date	Time	Platform
Ntkrnlpa.exe	6.0.6000.16514	3,504,824	28-Jun-2007	02:30	Not applicable
Ntoskrnl.exe	6.0.6000.16514	3,470,008	28-Jun-2007	02:30	Not applicable
Update-bf.mum	Not applicable	1,955	28-Jun-2007	14:20	Not applicable
Update.mum	Not applicable	2,669	28-Jun-2007	14:16	Not applicable
X86_b50c5078affe50966d4981c1c682bbfa_31bf3856ad364e35_6.0.6000.16514_none_4e65de02ad0fd904.manifest	Not applicable	697	28-Jun-2007	14:16	Not applicable
X86_cdd55a70af2e5c6188a8d6bc131b13de_31bf3856ad364e35_6.0.6000.20629_none_18c931a33e1e8c66.manifest	Not applicable	697	28-Jun-2007	14:16	Not applicable
X86_microsoft-windows-os-kernel_31bf3856ad364e35_6.0.6000.16514_none_6a435250b701059d.manifest	Not applicable	18,778	28-Jun-2007	14:20	Not applicable
X86_microsoft-windows-os-kernel_31bf3856ad364e35_6.0.6000.20629_none_6ac720a1d022400b.manifest	Not applicable	18,778	28-Jun-2007	14:20	Not applicable
Ntkrnlpa.exe	6.0.6000.20629	3,504,824	28-Jun-2007	02:29	Not applicable
Ntoskrnl.exe	6.0.6000.20629	3,470,520	28-Jun-2007	02:29	Not applicable

Windows Vista, 64-bit versions

File name	File version	File size	Date	Time	Platform
Amd64_0d92ac3011d1888ec4bc56a90c58a339_31bf3856ad364e35_6.0.6000.20629_none_07e3372044c7a02f.manifest	Not applicable	701	28-Jun-2007	14:16	Not applicable
Amd64_f290731b74e984b19bee0314aaf93bb7_31bf3856ad364e35_6.0.6000.16514_none_8a7cd3df0528f018.manifest	Not applicable	701	28-Jun-2007	14:16	Not applicable
Amd64_microsoft-windows-os-kernel_31bf3856ad364e35_6.0.6000.16514_none_c661edd46f5e76d3.manifest	Not applicable	17,330	28-Jun-2007	14:24	Not applicable
Amd64_microsoft-windows-os-kernel_31bf3856ad364e35_6.0.6000.20629_none_c6e5bc25887fb141.manifest	Not applicable	17,330	28-Jun-2007	14:24	Not applicable
Ntoskrnl.exe	6.0.6000.20629	4,431,544	28-Jun-2007	03:34	x64
Update-bf.mum	Not applicable	1,955	28-Jun-2007	14:20	Not applicable
Update.mum	Not applicable	2,669	28-Jun-2007	14:16	Not applicable
Ntoskrnl.exe	6.0.6000.16514	4,430,008	28-Jun-2007	03:36	x64

Back to the top

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Vista Service Pack 1.

Back to the top

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Back to the top