Failed to connect to a windows service. Windows could not connect to windows all user install agent service. This prevents standard users from logging in. As an administrative user, you can review the system event log for details about why the service didn't respond. I don't know how to review log and how to fix the problem if I do.

1) Have you made any changes prior to the issue?
2) When exactly do you get the error message?
3) Are you able to login to desktop?

Method 1: Check if the windows all users install agent service is started.

a. PressWindows Key + R, type services.msc, press ENTER.

b. Search for service namedWindows all user install agent service.

c. Windows all user install agent service should bemanual.

d. Check if it is started, if not Right click on the service and click onStart.

Method 2: Run System maintenance troubleshooter.
a. PressStart key on the keyboard.
b. Click on Control Panel.
c. Typetroubleshooting in the search tab and press Enter.
d. ClickView all on left panel.
e. ClickSystem Maintenance, new window will popup.
f. Follow the on screen instructions.

Method 3: Run System File Checker Scan to fix the issue with missing or corrupted files.
a. Press Windows key + X and click Command Prompt.
b. Type the command:sfc /scannow and press Enter.
c. Restart the computer and check.

Note:The System File Checker tool (SFC.exe) scans for missing or corrupted system files and repairs them.