Microsoft Windows Error Code 0xC0000099: How to Fix It

Medium 30-60 minutes Medium Severity Verified June 2026
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Error Code
0xC0000099
Brand
Microsoft Windows
Product Type
operating_system
Severity
Medium
DIY Difficulty
Medium
Estimated Fix Time
30-60 minutes
Error 0xC0000099 indicates STATUS_ALLOTTED_SPACE_EXCEEDED, meaning your system has insufficient allocated disk space to boot. This often occurs on small or full drives, especially when Windows is trying to create page files or temporary files during startup. Follow these steps to free up space and get your PC running again.
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Tools You'll Need

How to Fix Error Code 0xC0000099

  1. Boot from Windows Recovery Environment

  2. Check Disk Space Using DiskPart

    Be careful not to delete or modify partitions unless you know what you're doing.

  3. Delete Temporary Files Using Command Prompt

    Ensure you are targeting the correct drive letter (e.g., C:). If your system drive is D: in recovery, adjust accordingly.

  4. Use System Restore (If Available)

    System Restore requires that a restore point exists. If not, skip this step.

  5. Expand the Boot Partition (Advanced)

    Resizing partitions can cause data loss. Back up important data if possible.

  6. Perform Startup Repair

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When to Call a Professional

If you are unable to boot into recovery or the error persists after freeing up space and running Startup Repair, the issue may be a corrupted boot configuration or failing hard drive. In that case, contact a professional technician for data recovery or hardware diagnostics.

Frequently Asked Questions

What does error 0xC0000099 mean?
It means STATUS_ALLOTTED_SPACE_EXCEEDED, indicating that Windows cannot boot because there is not enough allocated disk space on the system partition.
Can I fix error 0xC0000099 without reinstalling Windows?
Yes, by freeing up disk space using recovery tools, deleting temporary files, or expanding the partition. Reinstalling should be a last resort.
How much free space does Windows need to boot?
Windows typically needs at least 1-2 GB of free space on the boot partition to create necessary temporary files and page files. For smooth operation, aim for 15-20% free space.
Will deleting temporary files delete my personal data?
No, deleting temporary files in the Windows\Temp folder does not affect your personal documents, photos, or installed programs.
What if I can't access the recovery environment?
If you cannot boot from a USB or DVD, you may need a friend's PC to create a recovery drive, or contact a technician for assistance.

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