Preparing a PC that has to stay reachable while you are away

Almost every "it worked yesterday" failure is the same thing: the computer is not refusing you, it is asleep. Ten minutes of settings before you leave prevents nearly all of it.

Sleep is the main culprit

A suspended machine has no network stack running. It is not reachable by anything, and from your side it is indistinguishable from a broken connection. Windows ships with aggressive sleep timers, and a desktop that is "always on" in your head is often asleep within thirty minutes of the last keypress.

On Windows: Settings → System → Power & battery → Screen and sleep, and set sleep to Never when plugged in. Leave the screen timeout alone — turning the display off saves the power that matters and does not affect reachability.

Two settings people miss after doing that:

• Hibernation and fast startup. These can still take the machine down even with sleep disabled. If reachability matters more than power draw, disable hibernation with powercfg /hibernate off from an elevated prompt.
• The network adapter's own power saving. Device Manager → your adapter → Properties → Power Management → uncheck "Allow the computer to turn off this device to save power". This one silently drops the link on a machine that is otherwise awake, and it is genuinely hard to diagnose.

On a laptop, add one more: closing the lid suspends by default regardless of everything above. If the laptop is the machine you need to reach, set the lid-close action to "Do nothing" while plugged in — and accept the thermal consequences of a closed laptop that stays awake.

The lock screen

A locked machine is still reachable, and it should stay locked — you want the desktop protected when nobody is at it. What you need is for your remote tool to work from the lock screen, which is a question of how it runs.

A tool that runs as a normal user application generally cannot show or interact with the lock screen, and often cannot see the User Account Control prompt either — so the session appears frozen the moment anything asks for elevation. A tool installed as a service or with an elevated helper can. If you install a remote access tool and it works fine until you lock the screen, this distinction is the reason.

Restarts you did not schedule

Windows Update reboots are the second most common cause of a machine being unreachable for a week. Two things help. Set your active hours so restarts happen when you would notice, and — more importantly — make the remote host application start automatically at boot rather than at login. A tool that only starts when someone logs in is useless after an unattended restart, because nobody logs in.

Test this properly before you rely on it: restart the machine, do not log in, walk away, and try to connect. That single test catches more problems than any amount of reading settings pages.

Power and network

• Put the machine on a UPS if a power blip would strand you. Cheap ones give enough runtime to ride out a flicker, which is the common case.
• Set the BIOS to power on after AC loss. Usually "Restore on AC Power Loss → Power On". This turns a power cut from a week of no access into a two-minute outage.
• Prefer Ethernet. More reliable, and it removes Wi-Fi driver power management from the list of things that can drop you.
• Check whether the router reboots on a schedule. Some ISP boxes do it nightly, and if the host does not reconnect on its own you will find out at the worst time.

A five-minute pre-flight before you travel

1. Restart the machine, do not log in, and connect remotely. If that works, most failure modes are covered.
2. Lock the screen and connect again. Confirm you can get past the login screen.
3. Trigger something that needs elevation and confirm the prompt is visible and clickable.
4. Check that the host app shows as running in the tray or service list after the restart.
5. Note the machine's code or ID somewhere you will have with you — not only on the machine you are leaving behind.

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