mxmidiout_vc12_x64.dll is an application DLL used by MAGIX Samplitude Music Studio 2019 Steam Edition. If Windows says the file is missing, not found, or could not be loaded, repair the Samplitude installation through Steam rather than copying a replacement into a Windows folder.
The file is a 64-bit MIDI or audio component for Samplitude, not a Windows system file and not the Microsoft Visual C++ runtime itself. The safest first repair is Steam’s built-in file verification.
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Fix 1: Verify Samplitude’s files in Steam
Time needed: 5–15 minutes
A damaged, incomplete, deleted, or quarantined application file is the most likely cause. Steam can compare the installed files with the product depot and restore missing or corrupted files.
- Close Samplitude.
- Exit Steam completely. Right-click the Steam icon in the notification area and choose Exit.
- Open Steam again.
- Select Library.
- Right-click Samplitude Music Studio 2019 Steam Edition.
- Choose Properties.
- Select Installed Files.
- Click Verify integrity of game files.
- Wait for the process to finish.
- Start Samplitude from Steam.
If Steam reports that files were replaced, launch the program again. A successful repair should remove the mxmidiout_vc12_x64.dll startup message.
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Steam may report that some local configuration files failed verification. That does not necessarily mean the repair failed. Configuration files can be changed during normal use. Focus on whether Steam reacquired the missing application file and whether Samplitude now starts.
If verification stops, reports a disk error, or restores the file every time you run it, continue with the quarantine and reinstall steps below.
Fix 2: Check antivirus quarantine
Time needed: 5–10 minutes
Security software can quarantine an application DLL after an update, a scan, or a false detection. Check the exact filename before reinstalling anything.
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- Open Start and select Windows Security.
- Choose Virus & threat protection.
- Select Protection history.
- Look for an action involving
mxmidiout_vc12_x64.dll. - Open the detection details and confirm that the affected path belongs to the Samplitude installation.
- If the file came from the legitimate Steam installation, follow Windows Security’s Restore or Allow on device option.
- Run Steam’s Verify integrity of game files procedure again.
The exact menu names can differ slightly after Windows Security updates. Third-party antivirus programs have their own quarantine and exclusion screens.
Do not permanently disable antivirus protection to make Samplitude start. If the file is quarantined repeatedly, scan the Steam installation, check the antivirus detection name, and reinstall Samplitude from Steam. Treat repeated quarantine as a security issue rather than repeatedly downloading the DLL from an unverified source.
Fix 3: Reinstall Samplitude through Steam
Time needed: 15–45 minutes, depending on download speed
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Use a reinstall when verification cannot restore the file, Samplitude contains mixed files from different versions, or the installation was interrupted.
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Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →- Open Steam.
- Select Library.
- Right-click Samplitude Music Studio 2019 Steam Edition.
- Choose Manage.
- Select Uninstall and confirm.
- Restart Steam.
- Install Samplitude again from your Steam Library.
- Allow the installation to finish without pausing or interrupting it.
- Run Verify integrity of game files once more.
- Start Samplitude.
Back up personal projects, templates, presets, and custom audio content before removing the application. Uninstalling the program may not remove every user-created file, but you should not rely on that.
If the same file disappears immediately after a clean reinstall, check antivirus history and the health of the drive. A failing disk, filesystem damage, or security software action can undo a successful installation.
Fix 4: Repair a separately named Visual C++ dependency
Time needed: 10–20 minutes
The vc12 part of the filename can resemble Microsoft Visual C++ 2013, also called VC++ 12.0. That naming similarity does not mean mxmidiout_vc12_x64.dll is included in the redistributable.
Install or repair Visual C++ only when the error names a Microsoft runtime such as:
msvcp120.dllmsvcr120.dll
Use Microsoft’s Visual C++ Redistributable downloads page, not a DLL download site.
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- Open the Microsoft page.
- Find the Visual Studio 2013 redistributable section.
- Download the official
vcredist_x64.exepackage for a 64-bit application. - Run the installer.
- Choose Repair if offered, or install it.
- Restart Windows.
- Try Samplitude again.
Some systems also contain separate 32-bit components that need the x86 package. Install x86 only when another 32-bit application or dependency specifically requires it. Do not substitute a 32-bit mxmidiout_vc12.dll for the _x64 file. The two names indicate different architectures, and mixing them can create another startup failure.
Fix 5: Check the installation path and architecture
Time needed: 5–10 minutes
The file should normally be beside the Samplitude program files inside the Steam installation directory. It does not belong in C:WindowsSystem32, C:WindowsSysWOW64, or another shared Windows folder.
To inspect the installation:
- Open Steam and select Library.
- Right-click Samplitude.
- Choose Properties.
- Select Installed Files.
- Click Browse.
- Search the opened folder for
mxmidiout_vc12_x64.dll.
If the file is present but Windows still reports that a module is missing, the named file may have a missing dependency. “The specified module could not be found” can refer to the DLL itself or to a DLL that it needs.
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Do not copy a similarly named 32-bit file into the folder. Do not combine files from another Samplitude release, another computer, or an unofficial archive.
Fix 6: Update audio and MIDI drivers only if the error points there
Time needed: 10–30 minutes
mxmidiout_vc12_x64.dll is part of Samplitude, so a driver update is not the primary repair. Consider this step when Samplitude starts after file verification but fails while opening an audio or MIDI device, or when Device Manager shows a device problem.
- Right-click Start.
- Select Device Manager.
- Expand Sound, video and game controllers.
- Expand Audio inputs and outputs.
- Expand Software devices if relevant.
- Look for a warning icon or a device that has disappeared.
- Right-click the affected device and choose Update driver.
- Select Search automatically for drivers.
- Restart Windows after the installation.
For professional audio hardware, prefer the manufacturer’s current driver and installation instructions. Do not remove a working MIDI or audio driver merely because the DLL name contains vc12.
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Searching for outdated drivers manually can mean checking several device models and package versions. Outbyte Driver Updater can show which drivers it identifies as outdated; its full version performs the driver installation. It is optional, and reinstalling Samplitude remains the definitive fix for this application DLL.
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Fix 7: Repair Windows components with DISM and SFC
Time needed: 15–30 minutes
DISM and System File Checker repair protected Windows components. They generally will not restore a third-party MAGIX DLL, so use them after repairing Samplitude or when other Windows programs also report damaged system files.
- Open Start.
- Type
Command Prompt. - Right-click Command Prompt.
- Select Run as administrator.
- Approve the User Account Control prompt.
- Run this command first:
DISM.exe /Online /Cleanup-Image /RestoreHealth
- Wait for DISM to finish.
- Then run:
sfc /scannow
- Restart Windows.
- Test Samplitude again.
Do not close the elevated window while either scan is running. If SFC reports that it found and repaired corrupted files, test the application after restarting. If both commands complete without fixing the Samplitude error, return to Steam verification and antivirus review.
Repeating SFC and DISM without knowing what changed makes troubleshooting harder. Outbyte PC Repair can scan for issues and show what it identifies; repair actions require its full version. It is optional, and it does not replace reinstalling Samplitude when the application DLL itself is missing.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Do not use regsvr32 for this file
Time needed: none
regsvr32 is for DLLs that provide registration entry points such as DllRegisterServer. There is no reliable public evidence that mxmidiout_vc12_x64.dll is a COM or ActiveX server.
Running this command is not a general DLL repair:
regsvr32 mxmidiout_vc12_x64.dll
It may produce an entry-point error and will not recreate a deleted file or install a missing dependency. Use registration only when the software vendor specifically instructs you to register a component.
Why this error happens
The likely causes, in practical order, are:
- An incomplete or corrupted Samplitude installation.
- Antivirus quarantine or deletion.
- Manual deletion, disk cleanup, or an interrupted update.
- Mixed files from different application versions.
- A missing dependency named separately in the error.
- A wrong 32-bit or 64-bit component.
- Disk or filesystem damage.
- Broader Windows component corruption.
The public file listing reports an approximate size of 89 KB and a file version of 0.0.0.0, but those values are third-party metadata rather than an official MAGIX specification. They should not be used alone to validate a replacement file.
What to do if the error remains
Record the complete error text, not just the filename. Also note:
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- The Samplitude executable path.
- The Steam library path.
- Whether Steam verification restored a file.
- Any antivirus detection or quarantine action.
- Any additional DLL named in the message.
- Whether the failure occurs before Samplitude opens or when an audio device loads.
If the error names another module, repair that dependency rather than replacing mxmidiout_vc12_x64.dll. If verification repeatedly fails, back up projects and check drive health before attempting another reinstall. Event Viewer or a dependency-analysis tool can help identify a missing module, but avoid downloading replacement DLLs from random websites.
Do these 3 things before closing this tab:
1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsFAQ
Is mxmidiout_vc12_x64.dll part of Windows?
No. It is an application-specific Samplitude component and should remain in the Samplitude installation directory.
Is it the Visual C++ 2013 runtime?
No. vc12 may refer to the compiler toolchain used to build the file, but the DLL itself is not a Microsoft redistributable file.
Can I download the file and copy it into System32?
No. That can introduce the wrong version or architecture and can create DLL search-order conflicts. Verify or reinstall Samplitude instead.
Is there a 32-bit version?
Public DLL listings include a similarly named mxmidiout_vc12.dll, but that does not establish that it belongs in this Steam installation. Do not use it as a substitute for the _x64 file.
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Should I enable a Windows Feature?
No Windows Feature is known to restore this application DLL. Do not enable random components as a replacement for Steam verification.
When should I reinstall Steam itself?
Only after verifying Samplitude, checking quarantine, and reinstalling Samplitude fail. If other Steam games also lose files or Steam cannot write to the library, repair the Steam installation or move the library after backing up important data.
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