Remote Desktop not working? Fixes for connection errors and a black screen

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   Step 1: Make sure the remote PC is on and awake

   A PC that's asleep, hibernating or shut down can't answer. On the remote PC, open Settings, then System, then Power (or Power & sleep), and set it never to sleep while it's plugged in.

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   Step 2: Check Remote Desktop is turned on, on a Pro edition

   On the remote PC, open Settings, then System, then Remote Desktop, and check the switch is on. If the page has no switch, the PC runs Windows Home, which can't accept Remote Desktop connections. Steps for both are in how to enable Remote Desktop on Windows 11 and 10.

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   Step 3: Test that the port answers

   On the PC you connect from, run this in PowerShell, with the remote PC's name or IP address:

   Test-NetConnection -ComputerName office-pc -Port 3389

   TcpTestSucceeded : True means the network side is fine and the problem is the sign-in or the display. False means something blocks the way: Windows Firewall on the remote PC, another firewall program, a changed port, or a different network. The RDP port 3389 guide shows how to check which port the PC uses.

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   Step 4: Try the IP address instead of the name

   PC names don't always resolve on home networks. On the remote PC, run ipconfig and use the IPv4 Address, such as 192.168.1.20. If the PC's address keeps changing, give it a DHCP reservation on the router.

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   Step 5: Check the account you sign in with

   Use the account's password, not its PIN. For an account that signs in to Windows with an email address, type the full email address. The account must be an administrator on the remote PC or listed under Remote Desktop users on its Remote Desktop settings page, and it needs a password.

"Remote Desktop can't connect to the remote computer"

Windows lists three reasons: remote access isn't enabled, the computer is turned off, or it isn't available on the network. That covers the first four checks above. If the PC is on and Remote Desktop is on but the port test fails, look at Windows Firewall on the remote PC: under Allow an app through firewall, Remote Desktop should be ticked for the type of network it's on.

"Your credentials did not work"

The user name or password was refused. Type the user name in full (the email address for an email sign-in, or PCNAME\username for a local account), use the password rather than the PIN, and clear any saved credentials under Show Options in Remote Desktop Connection before trying again.

"The connection was denied because the user account is not authorized for remote login"

The account isn't allowed to use Remote Desktop on that PC. Add it under Remote Desktop users on the remote PC, or sign in with an administrator account.

"An authentication error has occurred"

Usually one PC is missing security updates the other expects, or its date and time are wrong. Install Windows updates on both PCs, check the clock on each, and try again.

"Another user is signed in"

Windows 11 and 10 allow one person at a time. If you continue, the other person's session is disconnected (their apps stay open), and if they sign in again at the PC, yours is.

Try these in order, from quickest to most involved:

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   Step 1: Make Windows redraw

   Press Ctrl+Alt+End, then click Cancel. Or press Ctrl+Alt+Break twice to switch full screen off and on. Either one often brings the picture back.

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   Step 2: Restart the desktop if it's missing

   If you see a black screen with a pointer but no taskbar, press Ctrl+Alt+End, open Task Manager, choose Run new task (under File on Windows 10), type explorer.exe and press Enter.

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   Step 3: Turn off bitmap caching and lower the colors

   In Remote Desktop Connection, click Show Options. On the Experience tab, untick Persistent bitmap caching. On the Display tab, pick fewer colors, such as High Color (16 bit). Then connect again.

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   Step 4: Update the remote PC's graphics driver

   An old or broken display driver on the remote PC is a common cause, especially right after a Windows update. Install the latest driver from Windows Update's optional updates or from the PC or graphics card maker.

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   Step 5: Turn off UDP on the PC you connect from

   Some networks and routers handle Remote Desktop's UDP traffic badly, which shows up as a black or frozen screen. On a Pro PC, open the Local Group Policy Editor and enable Turn Off UDP On Client under Computer Configuration, Administrative Templates, Windows Components, Remote Desktop Services, Remote Desktop Connection Client. On any edition, run this in Command Prompt as administrator:

   reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services\Client" /v fClientDisableUDP /t REG_DWORD /d 1 /f

   Restart Remote Desktop Connection. The session then uses TCP only. To undo it, delete the fClientDisableUDP value.

A session that connects and then drops has its own set of causes. The usual ones for Windows Remote Desktop:

• The remote PC goes to sleep, or Windows turns off its network card to save power.
• A weak Wi-Fi signal at either end, or a network that changes, like a laptop moving between access points.
• Session time limits: Group Policy can end idle or long sessions (Remote Desktop Services, Remote Desktop Session Host, Session Time Limits). On a work PC, IT may have set them.
• A router that closes connections that look idle. Turning on Configure keep-alive connection interval, under Remote Desktop Session Host, Connections, helps.
• Someone signing in at the PC itself, which takes over from your session.
• UDP traffic being dropped on the way, or an old graphics driver on the remote PC, both fixed as in the black screen steps above.

Each cause and the setting that fixes it, step by step, is in remote desktop keeps disconnecting: causes and fixes.

Remote Desktop is built for the same network. From the internet, your router drops the connection unless port 3389 is forwarded to the PC, and forwarding it lets anyone on the internet try passwords against that PC. It also can't work if your internet provider shares one public address between customers, which is common on 4G, 5G and satellite internet; see remote access behind CGNAT. What forwarding involves, and how to limit the risk, is in the RDP port guide.

RemoteAccessApp doesn't use Windows' Remote Desktop at all. A small app, the Agent, runs on the PC and makes an outgoing connection to our relay, so most of the problems above don't apply:

• No Remote Desktop switch to turn on, and Windows 10 and 11 Home work the same as Pro. Linux desktops work too.
• No port forwarding and no firewall rule: the PC connects out, through ordinary home and office routers.
• It shows the desktop the person at the PC is already using, so nobody is signed out. They see a banner while you're connected, and they're asked first unless you switched on unattended access at that PC.
• Sessions reconnect by themselves when the network drops for a moment.

When a RemoteAccessApp PC won't open, the reason is usually one of these:

• It shows Offline. It's asleep, off, not online, or nobody has signed in to Windows since a restart. Click Why can't I connect? on its tile; the help article on can't connect to a PC explains each status.
• Nothing happens after you click it. The PC is waiting for someone there to click Allow. With nobody there, set up unattended access the next time you're at the PC.
• You can see the screen but clicks do nothing. A window running as administrator is in front. See an admin window is blocking my clicks.