Program file
steam_api64.dll: Valve's Steam library, a crack's emulator, or malware?
steam_api64.dll is the Steam Client API, a Valve library that 64-bit Steam games ship in their own folders. A copy in a game you bought on Steam is normal. Cracked games swap it for a Steam emulator, and free game downloads often bring malware with them, so a copy from any other source needs checking.
Prefer to check it yourself? The manual checks follow.
A steam_api64.dll in a game folder inside a Steam library (steamapps\common), describing itself as Steam Client API from Valve Corporation and signed by Valve, is the genuine file. It is not a process: the game loads it to talk to the Steam client. Every 64-bit Steamworks game has its own copy, so finding dozens of them is expected.
The name is the one file every crack for a Steam game replaces. A steam_api64.dll next to a .ini file or a settings folder, in a game that did not come from Steam, is a Steam emulator, and the download it came with is where malware usually hides.
- Publisher
- Valve Corporation
- Description in the file
- Steam Client API
- Shipped by
- Each 64-bit game built with the Steamworks SDK, in the game's own folder. The 32-bit games use steam_api.dll, a separate file
- Genuine folder
- The game's folder inside a Steam library, such as C:\Program Files (x86)\Steam\steamapps\common\<game>, next to the .exe or in an engine subfolder. Never in C:\Windows
- Size
- A few hundred kilobytes: about 110 KB to 410 KB across the 24 Valve copies collected in a public DLL catalogue
- Signed by
- Valve Corp. (check the signature; an emulator replacing it carries no Valve signature)
- Runs as a process
- No. It is a library loaded into the game that uses it
- Replaced by
- Steam emulators in cracked and repacked games, and some offline launchers and unlockers
What steam_api64.dll does
steam_api64.dll is the 64-bit library of the Steamworks API. Valve gives it to game developers with the Steamworks SDK, and its documentation tells them to ship it in the game's run-time directory, next to the executable. When the game starts, it calls the library to connect to the running Steam client, which then provides achievements, cloud saves, friends, invites, workshop items, multiplayer and the overlay.
The library also checks that the game was started with Steam and that the account owns it. That check is exactly what a crack has to remove, and the simplest way is to replace steam_api64.dll with a Steam emulator: a file with the same name and the same functions that answers the game itself and never asks Steam. The emulator is not malware in itself, but it is not Valve's file, and the download that brought it decides whether the PC is safe.
About .dll files. A .dll file is a library: it cannot run on its own and is loaded into a program's process. It does not appear in Task Manager under its own name; Process Explorer shows which process loaded it.
How to check a copy of steam_api64.dll
Four questions decide it: where the file is, what it says about itself, who signed it, and what sits next to it. A library never shows in Task Manager under its own name, so use these checks.
- List every copy and where it sits. Copies under a Steam library's steamapps\common folder are normal, one per 64-bit game. Look closer at copies in Downloads, Desktop, Temp, AppData, or a game folder outside any Steam library.
Get-ChildItem -Path C:\ -Filter steam_api64.dll -Recurse -ErrorAction SilentlyContinue | Select-Object FullName, Length, LastWriteTime - Read the version resource. Valve's file reports Valve Corporation as the company and Steam Client API as the description. An emulator often leaves these fields empty or different, though a careful one copies them, so this check alone does not clear a file.
(Get-Item "C:\path\to\steam_api64.dll").VersionInfo | Format-List CompanyName, FileDescription, FileVersion - Check the digital signature. Status Valid with a Valve signer means an unmodified Valve build. NotSigned, HashMismatch or another signer means the file is not Valve's as shipped. Text fields can be copied; a valid signature cannot.
Get-AuthenticodeSignature "C:\path\to\steam_api64.dll" | Format-List Status, SignerCertificate - Look at what sits next to it. Steam emulators usually come with their own configuration: a .ini file, a steam_settings or similar folder, or the original library kept under another name (steam_api64.dll.bak, steam_api64_o.dll). Any of these means the game folder was cracked or modified.
- Compare the size and checksum. Use the file check on this page. Valve's builds in the catalogue range from about 110 KB to 410 KB. A match identifies a known Valve copy; no match is not proof of a fake, because many Valve builds are not listed. The signature check above is the deciding one.
A valid Valve signature clears that one file. It says nothing about the .exe, installer or other files that came with a cracked game, which is where malware from such downloads is usually found.
Check your steam_api64.dll
Choose the steam_api64.dll you are unsure about. Its SHA-256 and SHA-1 checksums are calculated in your browser and compared with the 24 versions of the file known from a public DLL catalogue.
The file stays on your computer. Nothing is uploaded: the checksum is computed locally.
Do you need steam_api64.dll?
Keep every copy inside the Steam games you installed: without it the game does not start. A copy that failed the checks above comes with a game you got elsewhere, and the safe way out is to remove that game, not only the DLL.
- Leave Steam games alone. A copy in a steamapps\common game folder belongs to that game. If it is damaged or flagged, Steam restores Valve's copy for that game; deleting it only stops the game from starting.
- Uninstall a game that did not come from Steam. Open Settings, Apps, Installed apps, find the game and uninstall it. Repacks and free downloads often have no uninstaller: then delete the game's whole folder, not only steam_api64.dll.
- Run a Microsoft Defender full scan. Open Windows Security, Virus and threat protection, Scan options, Full scan. Quarantine what it finds. Look at Protection history afterwards for anything found in Downloads, Temp or AppData.
- Run the offline scan. Some malware bundled with game downloads hides while Windows runs. The offline scan restarts the PC and scans before Windows starts. It takes about 15 minutes.
Start-MpWDOScan - Check what starts with Windows. Open Task Manager, Startup apps, and Task Scheduler. Disable and remove entries that run a program from AppData, ProgramData or Temp that you do not recognise, after the scan.
- Change passwords if the download ran an installer you did not trust. Malware bundled with free game downloads is often an information stealer that takes saved browser passwords and session cookies, Steam and Discord logins included. Change passwords from a clean device and sign out of other sessions.
Warning signs
| What you see | What it means |
|---|---|
| steam_api64.dll next to a .ini file or a steam_settings folder | A Steam emulator from a crack, not Valve's file. |
| A steam_api64.dll.bak or steam_api64_o.dll in the same folder | The original Valve file was renamed and replaced. The folder was cracked or modified. |
| The signature check shows NotSigned or HashMismatch | The file is not an unmodified Valve build. |
| A steam_api64.dll in Downloads, Temp, AppData or outside any game folder | No game loads it there. Find out where it came from and scan. |
| The game came as a free download that asked you to turn off protection | The usual lure for malware bundled with cracked games. Remove the game and scan. |
| Dozens of copies, each in a steamapps\common game folder | Normal. Every 64-bit Steamworks game ships its own copy. |
Known versions of steam_api64.dll
A public DLL catalogue lists 24 versions of steam_api64.dll, from 1.10.1.46 to 5.25.65.21, by Valve Corporation. Its copies are uploaded by users and not verified, so a checksum match identifies the version, while the digital signature tells you whether the file is genuine. Even a genuine file clears only the file, not the folder: attackers ship genuine libraries next to a program they abuse, so where the copy sits still decides whether it is safe.
Every version with its checksums, and how to fix steam_api64.dll errors on uGetFix
Questions people ask
Is steam_api64.dll a virus?
No, Valve's steam_api64.dll is a harmless library that Steam games ship in their own folders. Security programs flag the name often because cracked games replace it with a Steam emulator, and the downloads that carry those emulators frequently bring malware too. A copy in a game you installed through Steam, signed by Valve, is the genuine file. A copy in a game from another source needs the checks on this page.
Why is steam_api64.dll flagged in a game I bought on Steam?
Because the name is so common in cracked downloads, some detections also hit Valve's genuine file. Check the signature: a valid Valve signature on a file in steamapps\common means it is the real library and the detection is false. Report it to the maker of your security program. Steam can restore the file if it was removed, through the game's Properties, Installed Files.
Is a cracked steam_api64.dll always malware?
No. A Steam emulator replaces Valve's file so the game runs without Steam, and many emulators do only that. The risk is the download it came in: repacks and free game sites are a common way to spread information stealers and other malware, in the installer or in other files of the game. Running cracked games also means you never know which part was changed.
How can I tell Valve's steam_api64.dll from an emulator?
Check four things. The folder: a game folder in a Steam library is where Valve's copy belongs. The signature: Get-AuthenticodeSignature should show Valid and Valve. The version resource: company Valve Corporation, description Steam Client API. And the neighbours: a .ini file, a settings folder or a renamed original next to it means an emulator, whatever the file says about itself.
Can I delete steam_api64.dll?
You can, but the game it belongs to stops starting, because every Steamworks game loads it at start-up. Deleting it from a Steam game gains nothing. If you found it in a game that did not come from Steam and you no longer trust that game, uninstall the whole game and run a Microsoft Defender full scan rather than deleting only the DLL.
Why are there so many copies of steam_api64.dll on my PC?
Each 64-bit game built with Steamworks ships its own copy, in the version of the SDK it was made with, so ten installed Steam games can mean ten copies of different sizes and versions. That is by design. What matters is that each copy sits in a game folder and carries Valve's signature, not how many there are.
What is the difference between steam_api.dll and steam_api64.dll?
steam_api.dll is the 32-bit Steam API library and steam_api64.dll the 64-bit one; both come from Valve with the Steamworks SDK. A game loads the one that matches its own build, and some ship both. The checks on this page apply to both files in the same way, and cracks replace both.
Sources
- Steamworks Documentation: Steamworks API Overview (shipping steam_api64.dll, SteamAPI_Init)
- Steam Support: Verify Integrity of Game Files
- MITRE ATT&CK T1574.001: Hijack Execution Flow: DLL
- Microsoft Learn: Get-AuthenticodeSignature
Version data read on Oct 14, 2026.
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