Windows Stop Code 0x00000038: SERIAL_DRIVER_INTERNAL

Quick Answer

SERIAL_DRIVER_INTERNAL (0x00000038) is a very infrequent Windows stop code. Microsoft publishes its name and value but does not specify a cause or a fix for this particular code. If it recurs, check recent serial device and driver changes, apply a targeted rollback or update where the evidence supports it, and examine the crash dump. The name alone does not identify a faulty COM port, USB adapter, or driver file. Microsoft Learn

What the Error Means

Windows uses different drivers and frameworks for serial communication. These include traditional COM ports, USB-connected serial ports, and serial controllers built into some devices. The published 0x38 description does not say which of these components was involved in a given crash, nor does it define diagnostic bug-check parameters. Use the PC’s configuration and crash evidence to narrow the cause. Microsoft Learn

Before You Begin

Record the stop code, crash time, and what happened just beforehand. Note any newly connected serial device, USB-to-serial adapter, expansion card, peripheral software, driver update, or Windows update. Save important work and back up data before changing drivers. Driver rollback requires administrator permissions. support.microsoft.com

Recommended Troubleshooting

1. Determine whether the crash repeats. Record a one-time crash and monitor the PC. For repeated crashes, look for a consistent trigger, such as connecting a device or opening an application that uses a serial port.
2. Isolate a recently added external device. Shut down, disconnect it, and restart. If crashes stop, check that device’s driver and compatibility before reconnecting it. support.microsoft.com
3. Check Device Manager. Right-click Start > Device Manager. Inspect any device marked with an exclamation point and the properties of a serial device that changed shortly before the crashes. A device may appear under Ports (COM & LPT) or another category, depending on its hardware and driver. Device Manager shows device status and driver information. Microsoft Learn
4. Roll back a relevant recent driver update. Right-click the identified device and select Properties > Driver > Roll Back Driver. Follow the prompts and restart if requested. If the option is unavailable, a previous driver may not be available.
5. Update a suspected driver if needed. Check Windows Update or obtain a compatible driver from the device manufacturer’s official site. Avoid downloading drivers from unrelated websites. support.microsoft.com
6. Install available Windows updates and test again. Make one targeted change at a time so that its effect is clear. support.microsoft.com

If a driver change makes the device unusable, roll it back where possible or reinstall the appropriate manufacturer driver. If Windows cannot start normally, use Safe Mode to investigate recent changes. support.microsoft.com

Advanced Troubleshooting: Examine the Crash Dump

For repeated crashes, preserve the newest memory dump. Small dumps are stored in %SystemRoot%\Minidump when that dump type is configured and successfully written. Other dump configurations commonly use %SystemRoot%\MEMORY.DMP. learn.microsoft.com

An IT professional can open the dump in WinDbg and run:

!analyze -v

Review the bug-check output and call stack, then compare any driver leads with the installed hardware and recent changes. A module shown in the analysis is a lead to investigate, not automatic proof that it caused the crash. learn.microsoft.com

Do not enable Driver Verifier as a routine first step on a production PC. Microsoft warns that it can cause crashes and recommends using it on computers intended for testing and debugging. learn.microsoft.com

How to Verify the Fix

Restart after the targeted change. Repeat the activity that previously preceded the crash and confirm that the serial device still works. If 0x00000038 returns, note the time and preserve the newest dump for further investigation.

Frequently Asked Questions

Does this stop code prove that Serial.sys is faulty?

No. Microsoft’s 0x38 page does not identify a driver file as the cause. Determine which driver is involved from the crash evidence. Microsoft Learn

Could a USB-to-serial adapter be relevant?

Yes, if it is installed and its use or installation matches the crash pattern. USB-connected serial ports have their own driver path, so do not assume every serial-related crash involves a traditional COM-port driver. Microsoft Learn

What if the PC has no visible COM port?

Verify the recorded stop code and examine the dump. The code’s name alone does not establish which serial-related component, if any, is visible to the user. Microsoft Learn

Should I replace the serial device immediately?

No. First check for a repeatable pattern and investigate the driver and dump. The published bug-check description does not establish a hardware failure. Microsoft Learn

Is there a command that reliably repairs 0x38?

Microsoft does not publish a repair command specific to this rare stop code. Choose a correction after identifying a plausible device or driver lead. Microsoft Learn

Conclusion

Stop code 0x00000038 provides little diagnostic detail on its own. For recurring crashes, isolate recent device changes, correct a supported driver lead, and use a crash dump to guide further investigation.

Sources

• Microsoft Learn, Bug Check 0x38: SERIAL_DRIVER_INTERNAL. Microsoft Learn
• Microsoft Learn, Serial Controller Driver Design Guide. Microsoft Learn
• Microsoft Support, Troubleshooting Windows unexpected restarts and stop code errors. support.microsoft.com
• Microsoft Support, Update drivers through Device Manager in Windows. support.microsoft.com
• Microsoft Learn, Stop code error or bug check troubleshooting. learn.microsoft.com
• Microsoft Learn, How to Use Driver Verifier for Driver Testing. learn.microsoft.com