A non-administrator receives:

The security log on this system is full. Only administrators can log on to fix the problem.

An attempt to log on remotely is greeted with:

The security log on this system is full.

Only members of the Administrators group can log on when the Security event log cannot be written.

To resolve this issue for the user:

1. Log on to the computer as a member of the Administrators group.

2. Start / Run / eventvwr.msc / OK.

3. Right-click Security and press Properties.

4. Either clear the event log, make it bigger, or check Overwrite events as needed.

5. Press OK.

6. Close the Event Viewer.

If you are going to Overwrite events as needed, you can use the following alternative:

1. Open a CMD.EXE window.

2. Type the following command:

REG ADD "HKLM\SYSTEM\CurrentControlSet\Services\Eventlog\Security" /V Retention /T REG_DWORD /D 0 /F