Things to check:

• Windows Update components stuck; try resetting the SoftwareDistribution and Catroot2 folders.
• Corrupted system files; “DISM /RestoreHealth” then “sfc /scannow”.
• Third-party AV or firewall interfering with update traffic.
• Disk nearly full or failing, causing write errors.
• Version end-of-life or driver blocks.

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What it might be (likely causes)

• Stuck update cache
  The SoftwareDistribution and Catroot2 folders hold temporary update files and catalogs. If they get corrupted, Windows Update can stall or error out.

A practical guide and case study: successfully troubleshooting and fixing an industrial dryer (early 2000s model) by replacing the main reservoir capacitor near the power supply transformer. Problem solved.