Windows update service doesn't start- 0x80080005

SFC scan get stucks @ 20%

Welcome to tenforums. I suggest you need to start with some basic checks.

1. Check your disk. Try
Hard Disk Sentinel (trial) - the best instant text report I know. Else e.g. HD Tune - Health and Error Scan tabs.
2. If ok, run
chkdsk c: /scan
from an admin command or Powershell prompt.

If this fails, run
chkdsk c: /F
- your PC will need to restart.

3. If ok, and something's been fixed, you can try
SFC /SCANNOW again.

4. If that fails again, I suggest you do an in-place upgrade repair install which keeps progs, data and most settings.
For that you need an iso of the same build as you now have -1809- (freely downloadable - see Heidoc iso downloader.

try In Settings Type in troubleshoot in search box choose available recommended troubleshooting
which will take you to a new page. Scroll down and choose windows update troubleshooter

Good SFC now passes. However service states may be incorrect or there may be other corruption.

If the troubleshooter fixes something and passes, obviously try again; if not, you can try
Reset Windows Update in Windows 10
and run the troubleshooter again.

If it still fails, I return to my suggestion - cut your losses, save time, and do an in-place upgrade repair install as above.

Thank you for your reply.

Have you ever disabled Windows Update?

Please follow last suggestion. Tutorial available if needed. Keeps all progs and data.
You will need an iso of the same build freely downloadable (search for Heidoc iso downloader).

Sound good. Upgrading your system, if successful, should have the same repair effect as an in-place upgrade repair install.