The C++ Standard Library implementation shared by almost every desktop program compiled in the last decade.

This module is delivered exclusively by the Microsoft Visual C++ Redistributable for Visual Studio 2015–2022. The familiar prompt The code execution cannot proceed because msvcp140.dll was not found means the redistributable is either absent or has been damaged on disk. The file is digitally signed and tightly version-locked; a copy lifted from another machine will fail the loader's integrity check or produce a fresh side-by-side configuration error.

Repair sequence

1. Obtain the redistributable from aka.ms/vs/17/release/vc_redist.x64.exe and aka.ms/vs/17/release/vc_redist.x86.exe.
2. Install both architectures — 64-bit applications routinely load 32-bit components for plugins and codecs.
3. Restart the workstation. The single install usually resolves the entire family of msvcp140* / vcruntime140* prompts.

A satellite module that holds symbols added after the original 14.0 ABI was published.

Machines stuck on the very first 2015 redistributable carry msvcp140.dll but not msvcp140_1.dll. Modern installers expect both files to be present in the same directory. The current 2022 redistributable is a strict superset of every earlier 14.x release and replaces the original 2015 package cleanly.

Repair

Install the latest 14.x redistributable from Microsoft. The newer installer overlays the 14.0 entry in Apps & Features.

The lower C-runtime layer the C++ standard library is built on top of.

When vcruntime140.dll is reported missing, the same redistributable that ships msvcp140.dll ships it. If the error persists immediately after installation, run sfc /scannow from an elevated terminal; the C runtime DLLs are tracked by Windows component servicing and a corrupted copy will be replaced from the protected component store.

Carries the runtime support introduced when MSVC adopted the C++17 exception-handling model.

The 32-bit redistributable does not ship this file because the 32-bit MSVC ABI uses an SEH-based mechanism instead. Install the x64 redistributable to satisfy the dependency. Pre-C++17 binaries never request it.

The pair of files delivered by the 2010 redistributable.

Source-engine titles from the Borderlands 2 / Dirt 3 era, several CAD packages and a long tail of engineering utilities still pin to this runtime, even on a current Windows 11 install. The 2010 package installs side-by-side with the 14.x runtime — uninstalling one does not affect the other.

Repair

1. Download Microsoft Visual C++ 2010 Redistributable Package (Service Pack 1) from Microsoft.
2. Install both the x64 and x86 packages.

The 2012-vintage runtime, paired with Visual Studio 2012's toolset v110.

Skype legacy installers, SQL Server 2012 tooling and the 2012–2014 generation of game launchers link against this version. Install Microsoft Visual C++ 2012 Redistributable Update 4 — the final servicing release — both architectures, from Microsoft's download archive.

The 12.0 runtime, shipped with the Visual Studio 2013 toolset.

The dependency surface here is enormous: Source-engine games (CS:GO, Dota 2 legacy builds), Autodesk products from the same period, and many embedded engineering tools require it. Install Microsoft Visual C++ 2013 Redistributable for both architectures.

A 2003-vintage C runtime that originally shipped with the .NET Framework 1.1.

Microsoft no longer publishes a redistributable for the 7.1 runtime. If a current application requests it, that application is an early-2000s build that expected the file to sit next to its own executable. Reinstall the application; in most cases its installer drops a private copy of msvcr71.dll into its program folder.

The Universal C Runtime variant invoked inside Virtualisation-Based Security enclaves.

This module is a Windows component and is not redistributable. An error referencing it almost always indicates servicing damage on an aggressively customised image — typically the result of an interrupted cumulative update.

Repair

sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
shutdown /r /t 0

The Universal Windows Platform sibling of the desktop C runtime.

This file is serviced by Windows Update rather than by the Visual C++ Redistributable. If it is missing, a Windows feature update has rolled back partway. Run Settings → Windows Update → Check for updates, then re-run the failing installer. The standalone Windows Update Troubleshooter clears stuck queues on the rare occasions Settings cannot.

The C++/CX core library used by UWP applications and Microsoft Store games.

Delivered through Windows itself and through the dedicated Visual C++ Redistributable for the Universal Windows Platform. The most reliable repair is re-registering the entire Store app surface:

Get-AppxPackage -AllUsers |
  ForEach-Object { Add-AppxPackage -DisableDevelopmentMode `
  -Register "$($_.InstallLocation)\AppXManifest.xml" }

Reboot. If the failure persists, follow with DISM /Online /Cleanup-Image /RestoreHealth — the missing component is in the servicing store, not on the user partition.

A virtual DLL name that forwards to whichever physical module currently implements the Universal C Runtime.

On Windows 7 and 8.1 this error is the signature of a missing KB2999226 (Universal CRT) update. On Windows 10 and 11 the UCRT is part of the operating system and cannot legitimately be absent — the error there indicates servicing damage.

Repair on Windows 7 / 8.1

1. Install pending Windows Updates. If the system is held at an earlier patch level, install KB2999226 manually from the Microsoft Update Catalog.
2. Install the latest 14.x Visual C++ Redistributable on top.

Repair on Windows 10 / 11

Run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth.

The most-cited missing-DLL error on Windows in the past decade.

This module is part of the legacy DirectX End-User Runtimes (June 2010) package. The forward-only runtime that ships inside Windows itself deliberately omits the numbered d3dx9_* builds. Install the June 2010 redistributable from microsoft.com, reboot, and the file becomes available system-wide.

An earlier Direct3D 9 utility build; identical repair path.

The DirectX June 2010 installer drops d3dx9_42.dll alongside its newer 9.43 sibling. Several titles pin this exact build because the engine team built against a specific update of the DirectX SDK.

Old numbered utility builds, typical of Xbox 360-era PC ports.

Installed by the same June 2010 redistributable. No standalone packages are published for individual versions.

The Direct3D 11 utility library for the same generation of titles.

Although newer compiler builds ship in Windows itself, the d3dx11 utility library is exclusive to the legacy redistributable. Installing the June 2010 package drops it into %SystemRoot%\System32 and the matching SysWOW64 directory.

The HLSL shader compiler pinned by a generation of D3D11 titles.

Newer compilers — d3dcompiler_47.dll — ship inside Windows. Games that statically link against the 43 build must source it from the legacy DirectX redistributable. No standalone single-file download from Microsoft exists.

The Direct3D 9 runtime proper — part of Windows, not redistributable.

If the OS-provided d3d9.dll is reported missing, the most common cause is a third-party wrapper (ReShade, DXVK, an overlay tool) that placed a substitute d3d9.dll next to the application and is now failing to load.

Repair

1. Check the application's install directory for a stray d3d9.dll. Rename or remove it; the OS-provided copy will then be picked up.
2. If the OS copy itself is in question, run sfc /scannow from an elevated terminal.

The X3DAudio 1.7 spatial-audio runtime used by 2010-era DirectX titles.

Installed by the DirectX End-User Runtimes (June 2010) package. No separate download exists.

The XInput 1.3 controller API the pre-Windows-8 game generation links against.

Windows 8 onward ships xinput1_4.dll together with an API-set forwarder. Games that pin 1.3 explicitly bypass the forwarder and look for the named DLL on disk. The DirectX June 2010 redistributable provides it.

An internal Windows Defender Application Control helper.

A protected OS component. An error here typically accompanies a stalled cumulative update or third-party tampering of the servicing stack. Run sfc /scannow, follow with DISM /Online /Cleanup-Image /RestoreHealth, then apply pending Windows Updates.

The 32-bit GPU-accelerated PhysX runtime, distributed inside the NVIDIA driver package.

This file is not bundled with games; it ships with the GeForce driver under the optional PhysX System Software component.

Repair

1. Reinstall the latest GeForce driver, ticking PhysX System Software in the custom-install screen.
2. If the failing title also ships a private PhysX installer (most do), run that from the game's redistributable folder.
3. On non-NVIDIA GPUs the CPU PhysX runtime is sufficient; rerun the game's installer to repair the CPU side.

A studio-specific wrapper that abstracts the PhysX SDK version a game was certified against.

This DLL is bundled inside the game folder. Verify the game's files through its launcher — Steam: Properties → Installed Files → Verify integrity; Epic, GOG and Ubisoft Connect provide equivalent verification commands.

The cross-platform 3D audio API used by id Tech titles, Blizzard games and a long tail of open-source projects.

Two implementations exist: the Creative Labs reference build and the OpenAL Soft community fork. Both expose the same ABI; either is acceptable.

Repair

1. Reinstall the application — most ship a private copy of openal32.dll alongside the executable.
2. If a system-wide install is required, run the official OpenAL Installer for Windows from openal.org.
3. For modern titles, OpenAL Soft's signed build is a drop-in replacement.

The reference MP3 encoder used by Audacity and dozens of legacy audio editors.

Distributed under the LGPL by the LAME project. Audacity 3.0 and later embed MP3 export internally and no longer require the file; earlier builds expect it inside %ProgramFiles%\Audacity\. Source the binary from lame.sourceforge.io or from the application vendor's documented mirror, never from a generic DLL aggregator.

The high-level Ogg Vorbis decoder wrapping libvorbis and libogg.

Distributed by the Xiph.Org Foundation under a BSD-style licence and embedded privately inside every application that uses it. Reinstall the application, or run the launcher's verification command.

The aggregated FFmpeg library used for decoding, encoding and screen capture inside many Windows tools.

There is no standardised ffmpeg.dll; every application builds its own FFmpeg with a specific codec set and ABI. A copy lifted from another tool will almost certainly fail. Reinstall the application that triggered the error.

The Steamworks client API, embedded inside every Steam-distributed game folder.

This file is application-specific: each game ships its own steam_api.dll alongside steam_api64.dll. Substituting one game's copy for another's at minimum causes DRM check-failures; at worst, Steam treats it as tampering.

Repair

1. In Steam: right-click the title → Properties → Installed Files → Verify integrity of game files.
2. Steam re-downloads steam_api.dll, steam_api64.dll and any other modified file.
3. If verification reports a permanent mismatch, uninstall and reinstall the title.

The runtime for Microsoft's retired Games-for-Windows-Live service.

The service is dead but several titles still link against the runtime at start. Install the Games for Windows Marketplace Client from Microsoft's archive — the only first-party source that still places xlive.dll system-wide. For titles known to ship community GFWL-removal patches (Fallout 3, Bulletstorm, the original Dark Souls release), the unofficial patch is the cleanest path.

The RAD Game Tools Bink Video codec, used for in-engine cinematics in a vast number of titles.

Ships inside the game folder, never system-wide. Verify the game files in the launcher, or reinstall the title.

An Inno Setup decompression helper. The error usually points at a corrupted download, not at a missing file.

isdone.dll is part of the installer; what is actually failing is the payload archive's CRC check during extraction.

Repair

1. Re-download the installer from the publisher's direct mirror. Verify the SHA-256 if the publisher publishes one.
2. Temporarily disable third-party real-time AV scanners — several heuristic engines have been observed clipping payloads mid-extract.
3. Confirm the destination drive has at least double the installer's compressed size in free space; isdone.dll errors also fire on insufficient working-directory space.

An auxiliary module shipped inside the Ubisoft Connect client (formerly Uplay).

Does not exist outside the launcher's installation tree.

Repair

1. Uninstall Ubisoft Connect via Apps & Features.
2. Download the current installer from ubisoft.com.
3. Relaunch the offending title. The first run reconstructs the auxiliary modules.

A wrapper module used by a specific Ubisoft engine generation; named after its internal codename.

Game-folder file. Verify files through the launcher; reinstall the title if verification cannot replace it.

A patch helper used by the older Uplay client during background updates.

The current Ubisoft Connect uses a different patch mechanism. Remove any leftover legacy Uplay client and install the current launcher from Ubisoft's site.

The boot-loader DLL of a small-scale game launcher.

Not distributed standalone and not redistributable. Reinstall the launcher from its publisher's site — third-party DLL aggregators do not carry the matching Authenticode signature, and the launcher checks the signature at start.

A vendor-bundled support DLL.

Exists exclusively inside its parent installer. Aggregator sites that claim to host it typically repackage unrelated binaries. Verify game files via the launcher; reinstall from the publisher if verification fails.

A self-update helper that several launchers ship — Battle.net, Riot Client and EA App all happen to use the same file name for completely unrelated binaries.

Reinstall whichever launcher is emitting the error. The DLL is part of the launcher's signed payload; an external copy will break the update flow.

A session-telemetry helper bundled by a small set of game installers. Despite the name, it has no relationship with Microsoft Exchange.

Reinstall the offending application. Where the publisher offers an offline installer, prefer that variant — it carries every helper module the online updater otherwise streams.

A feature module bundled by titles that include an in-game tutoring layer.

Game-folder file. Verify files in the launcher, or reinstall.

The Win32 kernel-services library — the gateway through which every Win32 application reaches the kernel.

Loaded into every Windows process at start. An error claiming it is missing means the operating system itself has been damaged and the boot path nevertheless succeeded.

Repair

1. Boot from Windows installation media (Repair your computer → Troubleshoot → Command Prompt).
2. From the recovery prompt, run sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows.
3. If servicing cannot complete the repair, perform an in-place upgrade install via the Windows ISO — the Keep my files option preserves user data and applications while replacing every system DLL.

The Native API surface that kernel32.dll sits on top of.

Genuinely missing only on a catastrophically damaged install. Most often the message is misleading: the loader was already failing on a different module and reported the closest parent in the chain. Run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth; if both report clean, capture the application's full crash log and trace the actual failing module.

The user-mode windowing, message-pump and basic GUI subsystem.

Loaded by every GUI program. If both sfc and DISM report a healthy component store, the error is being generated by an injected module rather than by the real user32.dll — inspect AutoRuns entries for global DLL injectors (overlay tools, accessibility shims, screen-capture utilities).

The Windows shell library — icons, file dialogs, right-click menus.

Never legitimately missing. Errors typically appear after a third-party theme patcher or shell replacement has crashed. Reverse any such modification first (UltraUXThemePatcher, StartIsBack, similar), then run sfc /scannow.

The Common Controls library — list-views, tree-views, toolbars. One of the few Windows DLLs that uses side-by-side versioning.

Two builds (5.x and 6.x) coexist. An application's manifest selects which one it loads. An error citing comctl32.dll usually points to a manifest mismatch rather than a missing file. Confirm the application's .manifest file requests the v6.0.0.0 controls assembly and remove any third-party alternative manifest placed in the application folder.

The Hardware Abstraction Layer — a boot-time module the kernel loads, not a user-mode DLL.

An error referencing hal.dll almost always appears as a boot failure (a BSOD or a boot-manager dialog), not as an application-launch error.

Repair

1. Run Startup Repair from the installation media.
2. From a recovery prompt: bootrec /fixboot and bootrec /rebuildbcd.
3. If the failure followed a driver install, boot to Last Known Good Configuration via advanced startup and roll the driver back.

An API-set forwarder for the Windows Runtime activation core.

OS-level, not redistributable. The forwarder is absent entirely on Windows 7 — applications that request it must be moved to a supported OS. On Windows 10 and 11, run pending Windows Updates and follow with the standard sfc / DISM servicing pair.

The Cryptography API: Next Generation — the gateway for every modern Windows TLS, BitLocker and WinRT cryptographic operation.

Never legitimately missing. Run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth; install pending Windows Updates, since several CNG hotfixes ship through cumulative updates.

An Explorer helper for the type-ahead search box and integrated find dialogs.

Part of the OS. Run sfc /scannow; if the file is genuinely absent, the underlying cause is partial servicing — apply pending Windows Updates and follow with DISM /Online /Cleanup-Image /RestoreHealth.

The legacy 32-bit OpenSSL 1.0.x core library.

Renamed to libcrypto-1_1.dll from OpenSSL 1.1.0 onwards. Modern applications no longer reference libeay32.dll. If a current installation still asks for it, the application is built against a 1.0.x branch — reinstall it. Do not source the DLL elsewhere, because the binary must match the application's accompanying ssleay32.dll at the exact ABI version.

The MySQL 5.x C-client library.

Newer applications use libmariadb.dll or the MySQL 8.x connector, both at different ABIs. Reinstall the application that emits the error; for legacy ODBC and integration tools, the MySQL Installer for Windows with Connector/C 6.1 provides a system-wide reference build.

A utility module embedded inside specific vendor tool installers.

Not a system component. Reinstall the application that emits the error. If the originating program is unclear, use Process Monitor (Sysinternals) with the filter Path contains eutil.dll; restart the failing program and Process Monitor reports the requesting process and its expected load directory.

A .NET Framework assembly used by the Chart control's design-time host.

Lives in %WINDIR%\Microsoft.NET\Framework\ alongside the rest of the framework. Repair the .NET Framework through Apps & Features → Microsoft .NET Framework → Modify → Repair, or install the latest .NET Framework redistributable from Microsoft. Restart Visual Studio or the application that depends on the chart control afterwards.

A vendor-specific export helper used inside its parent application.

Not a standalone library. Reinstall the application; the DLL is part of its signed payload.

A compression / asset-streaming helper used by a niche set of installers.

Build is private to its vendor and signed against that vendor's certificate. Reinstall the host application. Modern Windows DLL-load policies (Authenticode enforcement; Image Integrity for protected processes; AppLocker rules where deployed) actively refuse third-party copies.

Three example DLLs shipped inside specific application folders.

Each is built and signed by the application's vendor and exists nowhere else on disk.

Repair

1. Identify the host application with Process Monitor: filter on the DLL name, restart the failing program and observe the request path.
2. Reinstall from the original vendor.
3. If the vendor has wound down, contact their support archive — these modules are not redistributable.

Three more app-private DLLs typical of print-driver, scanner-helper and language-pack installers.

Reinstall the device driver from the manufacturer's website. For HP printers, the HP Smart app from the Microsoft Store delivers the current signed package without the legacy companion DLLs.

A cluster typical of point-of-sale, accounting and engineering software.

The naming convention reflects internal product codes rather than any standard library. Reinstall the application; if it uses a per-user installer (common in retail and POS deployments), uninstall the per-user copy first to avoid leftover state.

DLL names that look random because they are: vendor-internal product codes, not standard library names.

Reinstall the host application. If the host is unclear, use Process Monitor to capture the failing load — the request path reveals the host process.