Windows Update Error 0x80070015 — What It Means & How to Fix It

What Does This Error Mean?

Windows Update error 0x80070015 means 'The device is not ready.' Windows tried to access a drive or storage device during the update process, and the device was not available or not responding. This usually points to a problem with your hard drive, a pending disk check, or a corrupted Windows Update cache.

Affected Models

Windows 10
Windows 11
Windows 8.1

Common Causes

A scheduled CHKDSK disk check is pending and has not run yet, blocking update installation
The Windows Update download cache folder is corrupted or inaccessible
Your hard drive or SSD has errors or bad sectors causing read failures during the update process
A removable drive (USB, SD card, external HDD) that Windows is trying to access is not connected or not ready
The Windows Update service has lost access to its working folder due to a permission error

How to Fix It

Check if a CHKDSK scan is pending. Open Command Prompt as Administrator and type: chkntfs C: — then press Enter. If it says a dirty bit is set or a check is scheduled, type: chkdsk C: /f — then press Enter, type Y, and restart your PC to let it run.

A pending CHKDSK prevents many Windows operations including updates. Letting it run and complete clears the pending flag and often resolves this error immediately.
Clear the Windows Update cache. Open Command Prompt as Administrator. Run these commands one at a time: net stop wuauserv — then: net stop bits — then delete the cache by typing: rd /s /q C:\Windows\SoftwareDistribution — then restart the services: net start wuauserv and net start bits.

The SoftwareDistribution folder holds downloaded update files. Windows recreates it automatically when the services restart. Corrupted files in this folder are a very common cause of update errors.
Run the Windows Update Troubleshooter. Go to Settings > System > Troubleshoot > Other troubleshooters. Find 'Windows Update' and click 'Run.' The troubleshooter automatically detects and fixes common update problems including service issues and cache corruption.

The troubleshooter handles many of the same steps above automatically. It is a good first step for less technical users.
Check your hard drive health. Download CrystalDiskInfo (free from crystalmark.info) and check the SMART health status for your main drive. If it shows anything other than 'Good,' your drive may be causing read errors during the update process.

A failing drive cannot reliably write update files, which causes 0x80070015. If health is poor, back up your files and replace the drive before attempting updates again.
Disconnect all external drives and USB storage devices. Unplug any USB drives, SD cards, external hard drives, or USB hubs before running Windows Update again. Windows sometimes tries to access these devices during updates and fails if they are not responding correctly.

Even a USB drive you are not actively using can trigger this error if Windows tries to scan it during the update process. Disconnect everything non-essential before updating.

When to Call a Professional

If drive health tests show errors and the update still fails after all fixes, a technician can replace the failing drive and perform a clean Windows installation. Do not delay if drive health shows 'Caution' or 'Bad' — your data is at risk.

Frequently Asked Questions

What does 'device not ready' actually mean?

In Windows, 'device not ready' means Windows sent a request to a storage device and the device did not respond in time or signaled that it was not available. For an internal drive, this usually means the drive has a fault. For external storage, it usually means the drive is not properly connected or powered. During Windows Update, the update service needs reliable read and write access to your main drive — any hiccup causes this error.

I deleted SoftwareDistribution but the error came back. What now?

If the error returns after clearing the update cache, the problem is likely at the hardware level — your drive has intermittent errors. Run a full CHKDSK scan (chkdsk C: /f /r from an Administrator Command Prompt, scheduled for next restart) and let it complete. Also check drive health with CrystalDiskInfo. If errors persist on a healthy drive, try running: DISM /Online /Cleanup-Image /RestoreHealth to repair Windows component files.

Can I install the update manually to work around this error?

Yes — download the update directly from the Microsoft Update Catalog at catalog.update.microsoft.com. Search for the KB number shown in your Windows Update history. Download and run the standalone installer. This bypasses the Windows Update service and often succeeds when the automatic update fails.