How to fix Steam fatal error "Failed to load Steamui.dll"?

"Fatal error, failed to load steamui.dll" means the Steam client could not load one of its own files, so it closes before the window opens. Your games and saves are not in that file. Restart the PC and check Windows Security for a removed file first, then let Steam download its files again (Fix 2).

Facts checked on 16 October 2026. Steps written for the Steam client on Windows 11 (25H2 and 26H2) and Windows 10 22H2, read against Steam Support.

What "Fatal error, failed to load steamui.dll" means and where it comes from

The message "Fatal error, failed to load steamui.dll" is written by the Steam client itself. At start it needs steamui.dll, a file in the Steam folder, and when Windows cannot load it, Steam stops. People also meet it right after a first install, when the setup left a file unfinished.

Valve publishes no description of what is inside steamui.dll. The name and the failure point to the part of the client that draws the window, and nothing here depends on more than that. The file is not a Windows file and not part of a game, so a game, your saves and your login are not damaged by this error.

What causes the "Failed to load steamui.dll" error, from most to least likely

Valve gives no statistics for this message. The order below follows what Steam users report for it and the causes Steam Support lists for a client that crashes or will not open.

How to fix the "Failed to load steamui.dll" error

Fixes 1 to 3 are the ones users report most and they cost nothing: restart, check what was removed, then let Steam download its files again. Fixes 4 and 5 change how Steam starts. Fix 6 repairs Windows files and Fix 7 reinstalls Steam over itself, which keeps your games.

Fix 1. Close every Steam process, restart the PC and check what Windows Security removed

5 minutesNo riskEveryone. Start here, above all when the error began after an antivirus scan or a cleaner program.

Steam Support lists a restart of Steam and the computer as the first step for a client that crashes or will not open, because it releases locked files. It also warns that antivirus software can raise false alerts. If Windows Security removed steamui.dll, restoring it is faster than any repair.

1. Press Ctrl + Shift + Esc to open Task Manager.
2. On the Processes tab, select every entry whose name starts with Steam and select End task.
3. Restart the PC with Start > Power > Restart.
4. Open Windows Security > Virus & threat protection > Protection history.
5. Look for an entry named steamui.dll or for a file in your Steam folder. If you find one, open it, select Actions and then Restore.
6. Start Steam from its shortcut.

If you use another security program, open its quarantine list instead and look for the same file. Restore only a file in your Steam folder, never one from another place.

Fix 2. Move steamui.dll and libswscale aside so Steam downloads them again

5 minutesLow riskSteam worked before and now fails at every start. This is the fix users report most.

A file that is damaged or only half written fails to load. When it is gone, Steam downloads a new one while it updates. Moving the files to a folder, instead of deleting them, lets you put them back.

1. Exit Steam completely with Fix 1, steps 1 and 2.
2. Right-click the Steam shortcut and select Properties.
3. At the bottom of the window, select Open File Location. The Steam folder opens, by default C:\Program Files (x86)\Steam.
4. Create an empty folder on your desktop and name it steam-backup.
5. In the Steam folder, find steamui.dll and drag it into steam-backup.
6. Find the file libswscale-X.dll, where X is the version number, for example 3, 4 or 5. Drag it into steam-backup too.
7. Double-click steam.exe and wait while Steam updates and downloads files.

Fix 3. Move the bin and package folders out of the Steam folder

5 minutesLow riskFix 2 changed nothing, or the error comes back after every Steam update.

The bin and package folders hold the client's own program files and update packages. If a damaged file sits there, a new steamui.dll can fail the same way. With both folders gone, Steam builds them again at the next start.

1. Exit Steam completely with Fix 1, steps 1 and 2.
2. Open the Steam folder with Properties > Open File Location on the Steam shortcut, as in Fix 2.
3. Drag the package folder into the steam-backup folder from Fix 2.
4. Drag the bin folder into the same backup folder.
5. Double-click steam.exe. Steam downloads the missing files and starts.

Fix 4. Run Steam as an administrator

3 minutesLow riskThe error appears at the first launch after a new install, or Steam sits in a folder that normal users cannot write to.

If Steam cannot write its files into its folder, an update can stop halfway and leave steamui.dll unfinished. A start as administrator gives it the right to write. The old version of this page gave this step, and we kept it because it is quick and can be undone.

1. Exit Steam completely with Fix 1, steps 1 and 2.
2. Right-click the Steam shortcut or steam.exe and select Run as administrator. Select Yes when Windows asks.
3. If that works, right-click the shortcut again and select Properties.
4. Open the Compatibility tab and tick Run this program as an administrator.
5. Select Apply and OK.

Step by step, with Windows 11 screenshots: How to run a program as administrator or in compatibility mode

Fix 5. Start Steam with the client beta parameter

3 minutesLow riskFixes 1 to 4 did not help and you accept that Steam may install its beta client.

Users report that Steam starts with this parameter when the normal client keeps failing, because it fetches the client from the beta channel. We could not confirm this in a Valve document. The beta client can also have faults of its own.

1. Exit Steam completely with Fix 1, steps 1 and 2.
2. Right-click the Steam shortcut and select Properties.
3. On the Shortcut tab, click in the Target field and press End.
4. Type a space and then -clientbeta client_candidate. Keep the quotation marks around the path as they are.
5. Select Apply and OK, then start Steam from this shortcut.

"C:\Program Files (x86)\Steam\steam.exe" -clientbeta client_candidate

Fix 6. Repair Windows system files with SFC and DISM

20 to 40 minutesNo riskOther programs on the PC also show missing or damaged file errors, or Fixes 1 to 5 did not help.

Steam loads steamui.dll through Windows. If Windows' own files are damaged, a correct Steam file can still fail to load. SFC and DISM replace damaged Windows files and do not touch your games or your files.

1. Open an elevated command window. Right-click Start and select Terminal (Admin), or type cmd in the search box, right-click Command Prompt and select Run as administrator. Select Yes when Windows asks for permission.
2. Run DISM first. Type the command below and press Enter. DISM downloads clean copies of damaged components from Windows Update, so it can take several minutes. Wait until it says The operation completed successfully.

   DISM.exe /Online /Cleanup-Image /RestoreHealth

3. Run System File Checker. In the same window, type the command below and press Enter. Do not close the window until the verification reaches 100%.

   sfc /scannow

4. Read the result and restart. Compare the last message with the table below this guide, then restart the PC so that repaired files are loaded.

These steps were written for Windows 11 24H2 and 25H2. The full page with the other versions and what each result means: Run DISM and SFC to repair Windows system files

Fix 7. Install Steam again into the same folder

10 to 30 minutesRead the warningNothing above helped, or the error comes at the first launch after a failed install.

Steam Support: reinstalling "may fix potential issues with Steam client and service files. Installing into same location will preserve all installed games." The installer writes every client file again, including steamui.dll.

1. Exit Steam completely with Fix 1, steps 1 and 2.
2. Download the Steam installer from https://store.steampowered.com/about/ and run it.
3. When the installer asks for the folder, choose the folder where Steam already is, by default C:\Program Files (x86)\Steam.
4. Finish the setup, let Steam update and sign in with your account.

If Steam still says it failed to load steamui.dll: what to check and whom to ask

We found no log that records this message, because Steam stops before it writes one. Steam Support lists what lies outside Steam when the client keeps failing: programs that watch the disk, a failing drive and faulty memory. Check them in this order.

1. Close cleaner, optimizer, recording and overlay programs, and test Steam again. Steam Support names these as common interference.
2. Check the drive that holds Steam. Steam Support's path is This PC > right-click the drive > Properties > Tools > Error checking. The command version: Check a disk for errors (chkdsk)
3. Check the memory: press Windows key, type mdsched and run Windows Memory Diagnostic.
4. If you use a security program that is not Windows Security, add the Steam folder to its exceptions list, as Steam Support suggests for its own folders.
5. Open Steam Support at https://help.steampowered.com, choose the topic for a client that will not start and describe the message and what you tried.

• Hardware sign: files are damaged again soon after a repair, Windows shows other file errors or the PC restarts on its own. The drive or the memory is then the first suspect.
• Account sign: none. This error comes before you sign in, so your account, password and licenses are not the cause.

How to keep the steamui.dll error from coming back

Frequently asked questions

What does "Fatal error, failed to load steamui.dll" mean?

It means the Steam client could not load its own steamui.dll file at start and stopped. The file is in the Steam folder, by default C:\Program Files (x86)\Steam, and is part of the client, not of a game or Windows. Valve gives no description of what is inside. The usual causes are a file that is damaged after an interrupted update, a file removed by security software or missing write rights. Start with Fix 1 and Fix 2, which cost nothing and keep your games.

Is steamui.dll a virus, and can I download it from a DLL site?

No to both. A steamui.dll in the Steam folder is a normal Steam file. We could not confirm where else a genuine copy would sit, so a steamui.dll in another folder or sent to you in a message is a reason to scan it. Never download the file from a DLL site: it can be old or carry malware, and Steam downloads a matching copy itself when you move the old one aside, as Fix 2 shows. If Windows Security flagged the real file, restore it from Protection history.

Will I lose my games if I move steamui.dll, bin and package, or reinstall Steam?

No, if you follow the steps on this page. Games are in the steamapps folder, and Fixes 2 and 3 never touch it. Reinstalling by running the Steam installer into the same folder keeps all installed games, as Steam Support states. What does delete them is uninstalling Steam through Windows or any other way than installing over it. Copy steamapps to another drive first if you want a spare copy.

Should I run regsvr32 steamui.dll?

No. Old guides, including our own earlier version, suggested it, but we found no Valve or Microsoft source that says steamui.dll can be registered. Windows only registers a file that offers a registration entry, and for others regsvr32 just shows an error and changes nothing. The time is better spent on Fix 2 and Fix 3, which make Steam write its files again. If you ran the command already, it did no harm.

What does -clientbeta client_candidate do?

It starts Steam on its beta update channel instead of the normal one. Users report that this makes Steam finish its update when the normal client keeps showing the steamui.dll error, but Valve has no page that says so and we could not confirm it. The beta client can have bugs of its own. Remove the text from the Target field of the shortcut when Steam works again, as Fix 5 says.

I see "Failed to load steam.dll", not steamui.dll. Is it the same fix?

We found no source that ties "failed to load steam.dll" to this error. Steam.dll and steamui.dll are two different files. Steam.dll is the file older games look for, and its fix is in our guide to the Failed to find Steam error. If Steam itself shows the message, Fix 1, Fix 2 and Fix 7 are the safest to try, because they only make Steam write its own files again.

Steam shows "erro fatal" or "fatal error" in another language. Do the same steps work?

Yes. The message is the same, only the first words are translated, for example "Steam erro fatal" on Portuguese Windows. File names such as steamui.dll and libswscale-3.dll and the folder names bin, package and steamapps do not change. Menu names in File Explorer, Task Manager and Windows Security do, but they sit in the same places. If you cannot find an item, search for it in the Windows search box.

The error began yesterday and I changed nothing. Why?

Steam may have updated in the background and stopped halfway, or a security program may have removed or blocked a file. Users report both. We could not find a Valve notice that names a client update for this error. Check Protection history in Windows Security first (Fix 1), because a removed file can be restored in a minute, and then move steamui.dll aside (Fix 2). A power cut or crash during an update can leave the file unfinished too.

Do I have to be signed in or connected to the internet for the fixes?

The fixes themselves work offline until the last step. Steam needs an internet connection when it starts again, because it downloads steamui.dll, the libswscale file and the other client files from Valve's servers. If the download stops, Steam Support advises restarting your router and modem and trying another network. You do not need to sign in until Steam shows its sign-in window.