big sur 11.5.2

Can anyone help? When I haven't used my Mac Mini for a short while, my screen goes black, as it should do. But recently, it's acting strangely: if I hit a key, the screen only bursts into life for a couple of seconds, then it goes black again for a couple of seconds and then comes to life again...

Just got a used Mac Mini. When I got it, the seller had set up a dummy account. I booted into recovery, erased the physical disk (which contained two Macintosh HD-data drives), and then reinstalled Big Sir. I believe this should be sufficient for a complete wipe and reinstall. However, under...

Why does my Mac lock me out when I step away from the keyboard? The screen turns off. It only turns back on when I hit Cmd + Shift + R. It takes me to a lock screen with the default OS background.

MacBook Pro (Retina, 13-inch, Early 2015), has Latest OS, Big Sur, 11.5.2 (20G95), and System Firmware Version: 427.140.8.0.0. Whenever I try to boot it normally, into recovery mode, Safe mode there is a delay of 2 minutes between pressing the power button and the startup chime and apple...

Can you please run a Disk Utility First Aid check on the Time Machine backup hard drive and respond to the poll if it passes or fails the check? This is for users of Big Sur 11.5.2 and you use spinning disk hard drive(s) for TM backups. Please also indicate the type of Mac you have (e.g., 2013...