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0x00000023FAT_FILE_SYSTEMStop codeWidely reported

FAT_FILE_SYSTEM (0x23): what it means and how to fix it

Updated Oct 13, 2026 · Checked against Microsoft documentation · How this page is made

Quick answer

FAT_FILE_SYSTEM (0x00000023) indicates that Windows ran into a critical error inside the FAT file system driver. It is usually caused by file system corruption, damaged disk sectors, or driver issues reading a FAT-formatted drive. The quickest first step is scanning the drive for file system and sector errors using the Check Disk utility.

What it means

FAT_FILE_SYSTEM with bug check value 0x00000023 occurs when the operating system encounters an unrecoverable condition while reading or writing to a partition formatted with a FAT file system (such as FAT, FAT32, or exFAT). Windows halts execution to prevent disk corruption from spreading to other files.

Disk and sector corruption

Physical defects on a drive, such as bad sectors, or logical defects in the file table itself will trigger this halt. When Windows requests data from a sector that returns unreadable or invalid file headers, the FASTFAT file system driver cannot safely complete the operation. Corrupted storage controller drivers, specifically SCSI or IDE drivers, can also mangle data traveling between the drive and the operating system, producing the exact same failure.

Nonpaged pool memory exhaustion

Another documented cause is nonpaged pool memory depletion. The nonpaged pool is a reserved pool of physical system RAM used by the Windows kernel and drivers that cannot be paged out to disk. If this pool is completely exhausted, the file system driver crashes. A crash can also occur if available nonpaged pool memory is critically low during drive indexing operations while another kernel-mode driver simultaneously requests memory from that same pool.

Common causes

  • File system structural corruption or bad blocks (sectors) on a storage drive.
  • Corrupted SCSI or IDE storage controller drivers interfering with disk read and write operations.
  • Depletion of nonpaged pool memory in the Windows kernel.
  • Another kernel-mode driver requesting nonpaged pool memory while pool resources are already low during file indexing.

How to fix it

Safest and most likely fixes first. Readers' answers to "Did this fix it?" reorder this list over time.

  1. Run Check Disk to repair storage errors

    Use this first to scan for and fix structural file system errors and bad sectors on the disk.

    1. Right-click the Start button and select Terminal (Admin) or Command Prompt (Admin).
    2. Type chkdsk /f /r and press Enter.
    3. Press Y if prompted to schedule the volume check on the next system restart.
    4. Restart your computer and allow the disk scan to complete before logging in.
    Did this fix it?

  2. Inspect Event Viewer for drive and driver faults

    Use this to identify whether SCSI drivers, FASTFAT, or the Autochk utility recorded specific disk failures.

    1. Right-click the Start menu and select Event Viewer.
    2. Expand Windows Logs in the left sidebar.
    3. Click System and scan the list for error events sourced from SCSI or FASTFAT.
    4. Click Application and look for entries logged by Autochk following recent restarts.
    5. Note any specific drive letters or controller devices referenced in those log entries to isolate the failing hardware.
    Did this fix it?

  3. Temporarily disable active monitoring utilities

    Use this if the crash occurs while reading or writing files and third-party monitoring utilities might be interfering with disk operations.

    1. Open Settings and go to Installed Apps.
    2. Temporarily disable or uninstall third-party disk defragmentation software, backup utilities, or virus scanners that continuously monitor disk activity.
    3. Restart the PC and check if the blue screen recurs during regular file access.
    Did this fix it?

  4. Run manufacturer hardware diagnostics

    Use this if Check Disk finds persistent bad blocks or disk read errors remain unresolved.

    1. Restart your computer and press your manufacturer diagnostic key during startup (refer to your computer owner manual for the specific key, often F12, F2, or Esc).
    2. Select the built-in storage and memory diagnostics from the boot menu.
    3. Run an extended test on all connected internal drives.
    4. Replace the storage drive if the diagnostic reports hardware failure.
    Did this fix it?

  5. Increase physical RAM

    Use this if system logs confirm nonpaged pool memory depletion is exhausting kernel resources.

    1. Check your current memory usage in Task Manager under the Performance tab, paying attention to the Non-paged pool figure.
    2. Consult your motherboard or computer manual to identify compatible RAM types and maximum capacities.
    3. Install additional physical memory sticks to expand the total amount of RAM available to the Windows kernel.
    Did this fix it?

Is it just you?

25+ Microsoft Q&A threads discuss this. Most recent activity:

Checked Oct 10, 2026. Refreshed automatically every few days.

Sources

Frequently asked questions

What does bug check 0x00000023 mean?

It means Windows stopped operating because the FAT file system driver encountered a critical error, usually caused by disk corruption or nonpaged pool memory exhaustion.

Can a bad USB drive trigger error 0x23?

Yes. Most external flash drives and memory cards use FAT or exFAT formatting, and bad sectors or file corruption on those drives can trigger this blue screen when Windows attempts to read them.

What is the FASTFAT entry in Event Viewer?

FASTFAT is the core Windows driver responsible for handling FAT file systems. Error messages from it in the System Log point directly to read or write failures on FAT-formatted drives.

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