Windows Update error 0x80070020 files in use cannot update

Windows Update won't install because a file is locked. You get error 0x80070020, the update fails, and nothing you try seems to clear it. Fifteen years of remote support has taught me this error appears more often than it should, and it's almost always antivirus software or a background process holding the file hostage.

What Causes Windows Update Error 0x80070020 Files In Use Cannot Update?

The error code 0x80070020 is a Windows sharing violation. Technically, it means ERROR_SHARING_VIOLATION: the file you're trying to access is already open by another process, and Windows won't let you overwrite it. During Windows Update, this becomes catastrophic because the update process needs to replace or modify system files, and if something else has those files locked, the operation fails immediately.

The most common cause is antivirus software. Real-time protection scans every file operation in real time. When Windows Update tries to place new files in the system folders, the antivirus engine locks those files to scan them, creating a deadlock: Update wants to write, antivirus wants to read, neither backs down. This happens even with big-name security software like Windows Defender, Norton, McAfee, and Kaspersky.

The second major culprit is background processes holding open file handles. OneDrive, Dropbox, Windows Backup, BITS (Background Intelligent Transfer Service), and even legitimate system services can keep files open. When Update tries to replace them, you get the sharing violation. Sometimes it's obscure software you forgot about. Sometimes it's a system service that didn't properly release a file.

Corrupted update caches in the SoftwareDistribution and Catroot2 folders can also trigger this. If a prior update was interrupted or failed, the cache can become corrupted, causing the update service to repeatedly try and fail to access the same locked files. This typically requires a cache reset to resolve.

Windows Update Error 0x80070020 Quick Fix

More Windows Update Error 0x80070020 Solutions

Advanced Windows Update Error 0x80070020 Fixes

Why Error 0x80070020 Keeps Recurring (And How to Stop It)

Even after you fix the immediate error, the same issue can return if you don't address the root cause. If antivirus was the culprit, it will lock files again on the next major update. If a third-party application was blocking, it will do so again unless you uninstall it or add its folders to your antivirus exclusion list.

The key is recognizing that system files and update caches need protection from constant scanning. Most antivirus programmes allow you to whitelist specific folders. Add C:\Windows\SoftwareDistribution and C:\Windows\System32\catroot2 to your antivirus exclusion list. This tells your antivirus: "Don't scan these folders in real time." You're not disabling antivirus; you're just preventing it from scanning folders that should be left alone during updates.

Similarly, if you found a problematic third-party application (like a file sync tool, system optimiser, or backup software), either update it to the latest version or uninstall it. Outdated applications often have compatibility issues with newer Windows versions and can trigger file locking unexpectedly. If you really need the software, contact the vendor for a compatible version.

Preventing Windows Update Error 0x80070020 Files In Use Cannot Update

Free up disk space first. Windows Update needs at least 15-20 GB of free space on your system drive (C:\) to download, extract, and install updates. If you're running below 10 GB, clear temporary files, uninstall unused applications, and move large files to external storage. Use Disk Cleanup: press Win+R, type cleanmgr, and press Enter. Select your system drive and let it clean temporary files. This often frees 2-5 GB.

Exclude update folders from antivirus scanning. Open your antivirus software and find the exclusion list or whitelist settings. Add these two paths:

• C:\Windows\SoftwareDistribution
• C:\Windows\System32\catroot2

This prevents real-time scanning from locking files in these critical folders during updates. Most antivirus programmes have this setting under Settings > Exclusions, Whitelist, or Virus & threat protection. If you're unsure, check your antivirus vendor's support documentation.

Close background applications before major updates. Before installing Windows feature updates (not just security patches), close unnecessary applications: OneDrive, Dropbox, email clients, browser, file explorers beyond what you need. These applications hold file handles on system drives. A cleaner system means fewer file locking conflicts.

Run monthly preventive scans. Once monthly, open Command Prompt as Administrator and run these two commands to catch and repair corrupted files before they cause update failures:

• DISM /Online /Cleanup-Image /RestoreHealth
• sfc /scannow

This takes 25-30 minutes but catches issues early.

Schedule updates during idle times. Go to Settings > Update & Security > Windows Update > Change active hours. Set active hours to when you typically use your computer (e.g., 8 AM to 10 PM). Windows will automatically install updates outside these hours, usually late evening or early morning, when background processes are fewer and file locking is less likely.

Keep antivirus updated. Outdated antivirus definitions sometimes over-aggressively block legitimate system operations. Update your antivirus software frequently (most modern antivirus updates automatically). Consider using Windows Defender, which is built into Windows and is specifically tested for Windows Update compatibility.

Windows Update Error 0x80070020 Summary

Error 0x80070020 is a sharing violation: Windows Update cannot access or replace a file because another process has it locked. Antivirus real-time scanning is the culprit in most cases, followed by background applications and corrupted update caches. The fix escalates logically: disable antivirus and restart (70-80% success), then reset Windows Update components (60-70% success), then perform clean boot and manual installation (50-60% success). Prevention requires antivirus exclusions, adequate disk space, and monthly preventive scans. If you've exhausted the three solutions here and the error persists, the Windows installation itself may be corrupted, and an In-Place Upgrade or professional support may be necessary. Most users resolve this on the first or second attempt.