When the 99% progress is stuck, you can try the following methods in turn: 1. Make sure that the system disk retains at least 10GB of free space and cleans temporary files; 2. Restart the three services of Windows Update, BITS and Cryptographic Services; 3. Use the sfc /scannow command to scan and repair the system files; 4. Manually clear the Windows Update cache. In most cases, the above steps can solve the problem of stuttering updates. If it still cannot be solved, consider using official tools to upgrade and install and back up the data in advance.

When updating to the latest version of Windows, if the progress is stuck at 99% and the progress is not moving, this situation is really a headache. The problem may be in the corruption of system files, insufficient disk space, or abnormal background services. Don't rush to reinstall the system, try the following practical methods first.

Check if the disk space is sufficient

Windows updates require some temporary space to decompress and install new files. Even if your system disk looks like it still has a lot of space, it may fail due to too much fragmentation or the reserved space being occupied.

• The system disk (usually a C disk) is recommended to retain at least 10GB of free space.
• Temporary files can be cleared using the Disk Cleanup tool
• If it is a mechanical hard disk, it is recommended to run disk defragmentation; SSD does not require it

Sometimes third-party software takes up a lot of temporary space, such as browser cache or download tools. You can try to manually delete some unnecessary files, or automatically clean them with the system's own "Storage Awareness" function.

Restart Windows Update related services

Windows Update runs through several background services. If one of the services is stuck, progress can be stagnant.

You can restart the relevant services by following the steps below:

• Press Win R to open the run window, enter services.msc to enter to enter
• Find the following three services:
  • Windows Update
  • Background Intelligent Transfer Service (BITS)
  • Cryptographic Services
• Right-click to select "Restart"

After you complete, check the update progress. Sometimes you only need to restart these services to continue to advance.

Use the system file check tool to fix system errors

If the system files are corrupted, the update will also fail to complete. Windows comes with a system file checker that can help you scan and fix these problems.

The operation method is as follows:

• Open the command prompt as administrator (and right-click to select "Run as administrator" after searching for "cmd")
• Enter sfc /scannow and enter
• Wait for the scan to complete and check the results. If there are any corrupt files, they will be automatically repaired.

This process may take several minutes, and do not close the window during this process. After completion, restart the computer and try the update again.

Clear the Windows Update cache

Update packages downloaded by Windows Update are saved in a specific cache directory. If this part of the data is corrupted, it may also cause the progress to be stuck.

You can manually clear these caches:

• Also stop the Windows Update service mentioned above
• Open path: C:\Windows\SoftwareDistribution
• Delete all the files inside (or cut them to another place for backup)
• Start the Windows Update service again and check for updates

This step is equivalent to starting the update process over again, suitable for long-term stuck situations.

Basically these are the methods. In most cases, being stuck at 99% is not a hardware problem, but a system-level glitch. If you check it in order, it can usually be solved. If it really doesn't work, you can also consider using Microsoft's official Media Creation Tool to create installation media for upgrade and installation, but remember to back up important information in advance.

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