Fix: the application has failed to start because its side-by-side configuration is incorrect

The side-by-side configuration error means Windows could not find or read a shared part that a program's manifest asks for, so it stopped the program before it opened. Most often an old Visual C++ runtime or the program's own install is missing or damaged. Read the SideBySide error in Event Viewer first: it names the part.

Facts checked on 16 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What "side-by-side configuration is incorrect" means

The full message reads: The application has failed to start because its side-by-side configuration is incorrect. Please see the application event log or use the command-line sxstrace.exe tool for more detail. Selecting OK only closes the window; the program does not run.

Many Windows programs carry a small description called a manifest. It can be built into the .exe or sit next to it as a separate .manifest file. It lists shared components, called side-by-side assemblies, by name, version and processor type. Before the program starts, Windows reads that list and looks for every part. When one is missing, of the wrong type or unreadable, the application has failed to start side-by-side, and this window appears.

• The message tells you where to look. The event log and sxstrace name the missing part; the window does not.
• It is one program's problem. The error is not tied to a specific app: browsers, games and design programs all show it when their parts are missing.
• It is not a virus warning and not a hardware alarm. It is a loading failure.

Why you get the side by side configuration error

Microsoft's C++ troubleshooting page lists what makes this loading fail. The assembly named in the manifest is installed neither in WinSxS nor next to the program, a policy file redirects to a missing version, or the manifest is broken. In practice they sort like this.

Why a 64-bit PC can still miss the 32-bit runtime

A manifest names the processor type of every part it needs. Microsoft notes that 64-bit assemblies cannot be loaded in 32-bit processes. Many older programs and games are 32-bit, so on 64-bit Windows they still need the x86 package of their runtime. Having only the x64 package installed gives you exactly this error.

How to fix "side-by-side configuration is incorrect"

Fix 1 tells you which of the others to run. Fixes 2 and 3 solve most cases. Fix 4 is for a damaged manifest or config file and Fix 5 for a window at sign-in. Fixes 6 and 7 are for when the event says too little or many programs fail. Test the program after each fix.

Fix 1. Read the SideBySide error in Event Viewer to find the missing part

5 minutesNo riskEveryone. The error message itself tells you to see the application event log.

When Windows cannot load a program's side-by-side parts, it writes an error with the source SideBySide. That entry holds the program path and, in most cases, the part that could not be found, which the error window does not show.

1. Write down the file name in the title bar of the error window, such as chrome.exe or game.exe, then select OK.
2. Press Win + R, type eventvwr.msc and select OK.
3. Open Windows Logs > Application, then select Filter Current Log in the right pane.
4. In Event sources, tick SideBySide and select OK.
5. Select the newest Error at the time of the failure and read the General tab.
6. Note the program path and every part name, version and processor type the text mentions. If the Application log has nothing, repeat the filter in Windows Logs > System.

Fix 2. Install or repair the Visual C++ 2005 or 2008 runtime the program asks for

10 to 15 minutesLow riskThe event or trace names Microsoft.VC80.CRT (Visual C++ 2005) or Microsoft.VC90.CRT (Visual C++ 2008), or you have an older program and no event.

Programs built with Visual C++ 2005 and 2008 load their runtime as a side-by-side assembly from WinSxS. A new PC often has only the 2015 to 2022 runtime, which does not replace them. Each year's package installs next to the others and overwrites nothing.

1. Open Settings > Apps > Installed apps and type Visual C++ in the search box.
2. Look for Microsoft Visual C++ 2005 Redistributable or Microsoft Visual C++ 2008 Redistributable, with x86 and x64 in the name.
3. If the year the event names is there, select the three dots, then Modify and Repair.
4. If it is missing, open Microsoft's Latest supported Visual C++ Redistributable downloads page and get that year's package from its older versions section.
5. Install the x86 package. On 64-bit Windows install the x64 package of the same year too.
6. Restart the PC and start the program.

Step by step, including .NET Framework: How to repair Microsoft Visual C++ Redistributable and .NET Framework.

Fix 3. Repair or reinstall the program from its maker

10 to 20 minutesRead the warningThe event names the program's own folder or part, a browser fails, or the runtime is in place and it still fails.

A program can keep its manifest and private side-by-side parts in its own folder. Microsoft's C++ troubleshooting page shows that Windows looks there when a part is not in WinSxS and fails if it is missing. A fresh install puts those files back, and most installers add the runtime they need.

1. Press Win + R, type appwiz.cpl and select OK to open Programs and Features.
2. Select the failing program and choose Repair or Change if it is offered. Test the program.
3. If there is no repair or it did not help, right-click the program and select Uninstall.
4. Restart the PC.
5. Download the newest version from the maker's website or the store you bought it from, and install it.
6. Start the program before you change any other setting.

With the Settings app instead: Uninstall a program or app in Windows.

Fix 4. Restore a damaged manifest or config file next to the program

10 minutesRead the warningThe event names a .manifest or .config file in the program's folder, often with a line number, or you added a mod or patch.

Windows reads a separate manifest file such as program.exe.manifest from the program's folder when the .exe has none built in. If that file was edited, swapped by a mod or damaged, Windows cannot read the list of parts, so the side-by-side configuration is incorrect even with every runtime installed.

1. Open the folder from the event path in File Explorer. Select View > Show > File name extensions so you see .manifest and .config.
2. Find the file the event names, such as program.exe.manifest or program.exe.config.
3. If you added or changed it yourself, for a mod or a patch, put back the original from your backup.
4. If you do not have the original, use the program's Repair in Fix 3, which restores its own files.
5. Start the program and check Event Viewer for a new SideBySide error.

Fix 5. Stop the startup entry that launches a broken program at sign-in

10 minutesLow riskThe window appears when Windows starts or you sign in, and you did not open anything.

If the side-by-side error appears at boot, something in your startup list launches a program whose parts are gone, often the remains of a partly removed program. Disabling that entry stops the window without touching anything else.

1. Right-click Start, select Task Manager and open Startup apps.
2. Find the program from the error title bar or the event path. Right-click it and select Open file location to confirm it is the same file.
3. If you still use that program, run Fix 2 or Fix 3 for it instead. If you do not, right-click the entry and select Disable.
4. If it is not in the list, press Win + R, type taskschd.msc, open Task Scheduler Library and look for a task whose Actions tab starts the same file.
5. Right-click that task and select Disable. Do not touch tasks whose author is Microsoft.
6. Restart the PC and check whether the window returns.

Fix 6. Trace the program start with sxstrace to get the exact missing name

10 minutesNo riskThe event is missing or vague, or you installed the runtime and the program still fails.

sxstrace is the command-line tool the error message names. Microsoft documents it as the tool that diagnoses side-by-side problems on Windows 11 and Windows 10. It records each step of loading the manifest and shows which part could not be resolved.

1. Select Start, type cmd, right-click Command Prompt and select Run as administrator. Select Yes.
2. Type sxstrace trace -logfile:%TEMP%\sxstrace.etl and press Enter. Leave the window open; tracing runs until you stop it.
3. Start the failing program and wait for the side-by-side error. Select OK.
4. Go back to Command Prompt and answer its prompt to stop tracing. If there is no prompt, run sxstrace stoptrace.
5. Type sxstrace parse -logfile:%TEMP%\sxstrace.etl -outfile:%TEMP%\sxstrace.txt and press Enter.
6. Type notepad %TEMP%\sxstrace.txt and press Enter. Press Ctrl + F and search for ERROR.
7. Read the lines just above the error: they name the assembly, its version and its processor type. Use the x86 and x64 table above to pick the fix.

sxstrace trace -logfile:%TEMP%\sxstrace.etl
sxstrace parse -logfile:%TEMP%\sxstrace.etl -outfile:%TEMP%\sxstrace.txt -filter:program.exe
notepad %TEMP%\sxstrace.txt

The -filter: option keeps only the lines of one program; replace program.exe with the name from the error title bar, or leave the option out.

Fix 7. Repair the Windows component store with DISM and SFC

20 to 30 minutesNo riskSeveral programs fail with the same message, the trace names a Windows part, or nothing above helped.

Shared side-by-side parts come from the Windows component store in WinSxS. DISM repairs that store and SFC then restores damaged system files from it. On a healthy PC it changes nothing, so it comes last.

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

If the side-by-side error still appears

When one program still fails after Fixes 2 and 3, its installer is not putting the parts its manifest asks for on your PC, and only its maker can fix that. Send them the facts, not only the message.

1. Copy the text of the newest SideBySide error from Event Viewer (Fix 1).
2. Attach the sxstrace.txt file from Fix 6.
3. Run winver and copy the Windows version and OS build.
4. Send these to the program's support or official forum and ask which runtime its version needs.

• On a work or school PC, software policies may block installing runtimes. Ask your IT department before you change anything.
• Disk errors (Disk or Ntfs entries in the System log) point to a failing drive, which can damage WinSxS again. Check it with Check a disk for errors (chkdsk) and back up your files.
• The same failure with a code: if the window says The application was unable to start correctly (0xc0150002), see our 0xc0150002 guide, which covers the code family.
• Windows parts fail too and DISM cannot repair the store: an in-place repair that keeps your files is next, Reinstall Windows without losing files.

How to keep the side by side configuration error from coming back

Side-by-side errors come back when shared runtimes are removed, a program is half removed, or its files are edited. A few habits prevent most of them.

Frequently asked questions

What is "side by side configuration is incorrect"?

It is a Windows loading error. A program's manifest lists shared parts, called side-by-side assemblies, by name, version and processor type. Before the program opens, Windows looks for them in C:\Windows\WinSxS and in the program's folder. When one is missing, of the wrong type or unreadable, Windows stops the program and shows this message. The SideBySide error in Event Viewer names the part, and the fix is to install or restore that part.

How do I fix an incorrect side by side configuration?

Open Event Viewer, filter the Application log by the source SideBySide and read the newest error. If it names Microsoft.VC80.CRT or Microsoft.VC90.CRT, install the Visual C++ 2005 or 2008 Redistributable from Microsoft, x86 and on 64-bit Windows also x64. If it names the program's own part, repair or reinstall the program. If it appears at sign-in, disable the startup entry. Run DISM and SFC only when many programs fail.

How do I fix the side by side configuration error on Windows 10?

The same way as on Windows 11: read the SideBySide event, then install the runtime it names or reinstall the program. The window, the Event Viewer path and sxstrace are the same on Windows 10 22H2. Windows 10 left support on 14 October 2025, so it gets no new security fixes. Moving to Windows 11 alone does not fix the error, because the same runtime must be installed there too.

Does the side-by-side configuration error happen on Windows 11 and Windows 7?

Yes. The same message appears on Windows 11 25H2 and 26H2, and the sxstrace tool it names is documented by Microsoft for Windows 11 and Windows 10. On Windows 7 the cause and the fixes are the same, but Windows 7 has had no support since January 2020, and newer program versions may no longer install on it. If a current version of a program fails only on Windows 7, the program may simply no longer support that system.

How do I fix the side-by-side error in Chrome or another browser?

Reinstall the browser from its maker. A browser carries its own manifest and parts in its install folder, and a failed update can leave them incomplete, which matches the most common cause after missing runtimes. Sign in to the browser's sync first so bookmarks and passwords return. Then uninstall it, restart, download the current installer from the maker's site and install it. If it still fails, read the SideBySide event to see which part it names.

What about "side by side configuration is incorrect" in Valorant or Riot games?

The cause is the same as for any program: a part named in the game's or launcher's manifest is missing. Read the SideBySide event first, because it names the exact file. Games often need an older Visual C++ runtime in the x86 version, so install the year the event names. If the event names the launcher's own folder, repair or reinstall the launcher from the maker's site. We could not confirm a Riot-specific cause.

Is "side to side configuration is incorrect" a different error?

No. "Side to side" is a common way of mistyping side-by-side, and the error behind it is the same one. Windows always writes it as side-by-side configuration. Searches such as side by side error, incorrect side by side configuration and the application has failed to start side by side also mean this same message, and the fixes on this page apply to all of them.

Can I fix it by downloading a missing DLL?

No. Side-by-side parts are registered in WinSxS with a manifest, a version and a processor type, so a single DLL copied into a folder does not satisfy the program. DLL download sites also carry wrong versions and sometimes malware. Install the Visual C++ Redistributable from Microsoft or reinstall the program from its maker. Those put every file and manifest where Windows looks for them.

Is the side-by-side configuration error a virus?

No, the message itself is not a virus warning. It is a loading failure that Windows shows for any program whose side-by-side parts are missing. It is worth a malware scan only when the event names a file you never installed, especially one in a Temp or AppData folder that starts by itself. In that case run a full Microsoft Defender scan before you delete anything.

Can this error appear on a Mac?

Not from macOS itself. The message comes from Windows, so on a Mac you see it only inside Windows running in a virtual machine or Boot Camp, or in a layer that runs Windows programs. Inside Windows the fixes on this page apply. In a layer that only imitates Windows, install the Visual C++ runtime the program needs through that layer's own tools, as its maker describes.