authenticating lock screen gone weird
iMac (27-inch Mid 2011), Mac OS X (10.7.5)
Hi Marlene,
You either have a Corrpt Fnt, or possibly installed some new bad font.
Bootup holding CMD+r, or the Option/alt key to boot from the Restore partition & use Disk Utility from there to Repair the Disk, then Repair Permissions.
If that doesn't help Reinstall the OS.
authenticating lock screen gone weird