How to use WinDbg to analyze dump files and resolve BSOD errors

When a computer with Windows When faced with an unexpected critical error, it usually displays a dreaded blue screen, also known as BSOD (Blue Screen of Death). Although for many users this type of error may seem like the end, it can actually be a gateway to understanding what's wrong with the system. Thanks to tools like WinDbg Now, with the dump files generated by the system, it is possible to diagnose the origin of the problem with a fair degree of precision.

This item is a A detailed guide to understanding what .dmp files are and how to analyze them with WinDbg and what other resources we can use to identify the cause of BSOD errors. If you've experienced unexpected reboots, random crashes, or unexplained blue screens, here's a complete guide to detecting and solving the problem.

What is a BSOD and what causes it?

A BSOD occurs when Windows cannot continue operating due to a serious error. At this point, the system stops running, displays technical information, and, by default, generates a memory dump file. This file contains essential data to understand what went wrong: loaded drivers, processor context, running threads, and more.

The most common causes of a BSOD may include:

• Driver errors, poorly designed or incompatible.
• Failures of hardware, such as faulty RAM modules or damaged disks.
• malicious programs (malware) that alter the system or cause file corruption.
• Internal configuration problems of the operating system (registry, overheating, etc.).

What does a memory dump file contain?

The .dmp (dump) file contains key information about the state of the system at the time of the failureThis file allows you to replay, almost frame by frame, what happened just before the error. The data it stores includes:

• El stop code and its parameters.
• List of active system drivers at the time of the error.
• Processor context and kernel (PRCB, EPROCESS, ETHREAD).
• Kernel-mode call stack of the active process.

This gives access to a very accurate picture of which parts of the system were causing conflict.

Where to find the dump files

Depending on the system configuration, dumps are stored in the following paths:

• C:\Windows\Minidump\: small dumps (minidumps).
• C: \ Windows \ MEMORY.DMP: kernel dumps or full dumps.

To view or change settings, go to Settings > System > Information > Advanced Settings and access Start and recoveryThere you can select the type of dump you want generated.

Types of memory dumps

Windows allows you to choose between different types of dumps depending on the level of detail:

1. Full dump: Captures all system RAM. Very detailed, but cumbersome.
2. Kernel dump: Only the essential part of the operating system. Balanced between detail and size.
3. Minidump: only minimal information, such as the error and stack. It typically takes up about 64 KB.

For a full dump to work correctly, The paging file must be on the same partition as the system and there must be enough disk space.

Introduction to WinDbg

WinDbg is a debugging tool developed by Microsoft. It is free and can be downloaded from the Microsoft Store , the WinDbg PreviewIts revamped interface makes the analysis process more intuitive.

The application allows you to read memory dumps, interpret the error, and display which drivers or processes are involved in the failure.

One of the keys to making WinDbg provide useful information is to add the path to Symbols from Microsoft. This allows functions and structures to be correctly identified during analysis.

Initial configuration of WinDbg

Once you have downloaded WinDbg Preview from the Microsoft Store:

1. Open the app from the Start menu or Windows Search.
2. Go to File > Settings > Debugging Settings.
3. En Default Symbol Path, enter the following: srv*https://msdl.microsoft.com/download/symbols
4. Click on OK to save the settings. This will allow the appropriate symbols to be downloaded during the analysis.

How to open and analyze a dump in WinDbg

With WinDbg already configured, follow these steps:

1. Go to File > Open dump file.
2. Select the .dmp file you want to analyze. If it is in C: \ Windows \ minidump or in the system directory, you must open WinDbg as administrator.
3. Once the file is loaded, type the command !analyze -v and press Intro.

WinDbg will display the complete analysis with error code, file or module involved, type of failure and suggestions.

What does the analysis result mean?

The report generated after the !analyze -v will include information such as:

• BUGCHECK_CODE: the BSOD code.
• MODULE_NAME o IMAGE_NAME: the responsible file.
• STACK_TEXT: the call stack to understand how it got to that point.
• IRQL, DEVICE_OBJECT, DRIVER_OBJECT: execution metadata.

An example would be an error like DRIVER_POWER_STATE_FAILURE (0x0000009F), which indicates that a controller did not respond correctly to a state change in a system with power-saving features.

Analysis example: USB failure

A case documented in several technical forums shows how a BSOD by MULTIPLE_IRP_COMPLETE_REQUESTS pointed to the file usbehci.sys. This suggested a problem with the driver USB. However, analyzing the IRP involved in detail, the file also appeared ax88172.sys, which corresponded to a network card connected via USB. The conflict between the two drivers caused the failure.

This type of analysis helps to Distinguish errors caused by Microsoft drivers from those caused by third-party hardware or drivers.

Use Driver Verifier

Approximately 75% of blue screens are related to faulty drivers. Windows has included a tool for years called Driver Verifier. Allows you to test active drivers and detect hidden errors.

To activate it:

1. Open a console as administrator (search DCM and right click).
2. Write verifier and press Enter.
3. Select the option to check for all unsigned or custom drivers.
4. Restart your computer when prompted. From that point on, the system will check the drivers' behavior in real time.

It is advisable to use this tool with caution, as it may slow down your system or even prevent it from working. Boot. If problems arise, it can be disabled from Safe Mode with the same command verifier and selecting “Delete existing settings”.

Tips for debugging persistent errors

In some cases, direct dump analysis will not yield conclusive results. For these scenarios, it's helpful to gather more information:

• Check the Event Viewer to view crash logs.
• Try with a LiveCD of Linux if a hardware failure is suspected.
• Run tools like MemTest86 to check the RAM.
• Use programs like BlueScreenView, more visual and end-user oriented.

Common BSOD errors and their causes

Some error messages are very common and well-documented. Here are some examples and what they typically mean:

• IRQL NOT LESS OR EQUAL: : faulty controller or improper memory access.
• KERNEL_MODE_EXCEPTION_NOT_HANDLED: : error within the kernel due to hardware or driver.
• PAGE_FAULT_IN_NONPAGED_AREA: access to an invalid memory address.
• DRIVER_IRQL_NOT_LESS_OR_EQUAL: Improper access to restricted variables in drivers.

In all these cases, the .sys file mentioned in the analysis is often crucial to determining whether the source is hardware, system, or third-party software.

Can anything be done if the BSOD appears and the system is rebooted?

Yes. Most systems are configured to automatically reboot upon a BSOD. This may prevent you from seeing the message altogether. To ensure it displays and generates the dump correctly:

1. Ir a Advanced system settings > Startup and recovery.
2. Uncheck the option Reboot automatically.
3. Make sure the option to create a memory dump is enabled.

This way, the next time you experience a BSOD, you can note the error and ensure the .dmp file is created correctly for later analysis.

Thanks to tools like WinDbgIt's entirely possible to diagnose the source of a blue screen error. Although reading a dump file may seem complex at first, with the right setup and some practice, you can gain invaluable insight into your system's internal state. BSOD analysis is essential for advanced users and technicians when troubleshooting, allowing them to effectively identify and resolve errors.