Side-by-Side Configuration Is Incorrect (Error 14001)

Q: Is this the same as 0xc000007b?

No. Side-by-side is Win32 ERROR_SXS_CANT_GEN_ACTCTX (14001)—a different code and mechanism from 0xc000007b.

Q: What should I check before installing Visual C++?

Read Event Viewer Application logs from source SideBySide (or run sxstrace). Note the assembly name and version, then install the matching official package. Do not use an unofficial all-in-one pack.

Recognize the message

Windows typically says the application failed to start because its side-by-side configuration is incorrect, and points you to the application event log or sxstrace.exe. Official wording is documented under system error code 14001.

Diagnose first (then install)

Open Event Viewer → Windows Logs → Application. Filter or look for source SideBySide. Note the missing or conflicting assembly name and version (for example Microsoft.VC80.CRT).
Optional detail: in an elevated Command Prompt, run sxstrace trace -logfile:sxstrace.etl, reproduce the failure, stop the trace, then sxstrace parse -logfile:sxstrace.etl -outfile:sxstrace.txt (sxstrace command reference; walkthrough: diagnosing SideBySide failures).
If the log names a Microsoft.VC*.CRT / MFC assembly, install the matching version and architecture from Microsoft—not a third-party “every year” pack. Modern v14 runtimes use the official page below; older VC80/90/100 packages are listed on that same Learn page under legacy sections.

Open the official Visual C++ Redistributable page on Microsoft Learn On that page, choose the X86 and/or X64 button that matches your app. We never host DLL files.

Need help mapping DLL names like msvcp140 / vcruntime140 after you already know it is a v14 runtime issue? See msvcp140 dll was not found.

If 0xc000007b appears too

Side-by-side and bad-image failures can show up close together when dependencies are broken. If you also get 0xc000007b, switch to bitness / the dialog page—do not assume one Visual C++ install fixed both without checking the SideBySide assembly name.

FAQ

Is this the same as 0xc000007b?

No. Side-by-side is Win32 ERROR_SXS_CANT_GEN_ACTCTX (14001)— a different code and mechanism from 0xc000007b.

What should I check before installing Visual C++?

Read Event Viewer Application logs from source SideBySide (or run sxstrace). Note the assembly name and version, then install the matching official package. Do not use an unofficial all-in-one pack.

What if I also see 0xc000007b?

Switch to the dialog page and home bitness / runtime steps. Do not assume one Visual C++ install fixed both without checking the SideBySide assembly name.