How to fix .NET Runtime error 1026 (Event ID 1026) in Windows?

Event ID 1026 from the source .NET Runtime means one program built on .NET crashed because of an error it did not handle. The event names the program and the error type in its Exception Info line. Read that line first, because it decides the fix: most often an update or reinstall of the program named in the event.

Facts checked on 15 October 2026. Steps written for Windows 11 (25H2 and 26H2) and Windows 10 22H2.

What .NET Runtime Event ID 1026 means and how to read it

Event ID 1026 is an entry in the Application log from the source .NET Runtime, level Error, keywords Classic. Windows writes it when a program that runs on .NET hits an error, called an exception, that the program's own code does not handle. The .NET runtime then ends the process and logs what happened.

Event ID 1026 as Microsoft shows it in a SharePoint support article (shortened)

Log Name: Application
Source: .NET Runtime
Event ID: 1026
Level: Error
Application: stsadm.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.IO.FileNotFoundException
at Microsoft.SharePoint.StsAdmin.SPStsAdmin..cctor()
Exception Info: System.TypeInitializationException
at Microsoft.SharePoint.StsAdmin.SPStsAdmin.Main(System.String[])

• Application is the program file that crashed. On your PC it reads Application: [program].exe with the real name. This is the program to fix, not Windows.
• Framework Version: v4.0.30319 means the program runs on .NET Framework 4.x. Every 4.x version, up to 4.8.1 on Windows 11, reports this same number.
• Description is always the same sentence. It says the crash happened, not why.
• Exception Info names the error type. When there are several, the first one is the root error and the later ones only wrap it. In Microsoft's example the root error is a missing file (FileNotFoundException).
• The "at" lines show where in the program's code the error happened. You do not need to understand them, but the program's support team does.

Why .NET Runtime error 1026 happens: causes ranked

The Exception Info line separates the causes. We have no counts of how often each one occurs, so the order below follows the examples in Microsoft's support articles and the reports we read: problems inside the program first, damaged .NET Framework files rarely.

How to fix .NET Runtime error 1026

Fix 1 takes five minutes and tells you which of the others is yours. Fixes 2 and 3 cover most single program crashes. Fixes 4 to 7 are for crashes that affect several programs or keep coming back. You do not need to work through all of them.

Fix 1. Open event 1026 and read the Application and Exception Info lines

5 minutesNo riskEveryone who saw .NET Runtime error 1026 and does not yet know which program and error it is.

Event 1026 is a crash report, and its two key lines tell you which program failed and why. Without them, every fix below is a guess.

1. Press Win + R, type eventvwr and select OK.
2. Expand Windows Logs and select Application.
3. Select Filter Current Log in the right pane.
4. Open the Event sources list, tick .NET Runtime, type 1026 in the event ID box and select OK.
5. Double-click the newest event and read the General tab.
6. Note the name after Application: and the first line that starts with Exception Info:.
7. Select Copy at the bottom of the window and paste the text into Notepad. You will need it if the fixes below do not help.

Prefer one command? This lists the last five 1026 events with their full text. Run it in Terminal or Windows PowerShell; it does not need administrator rights for the Application log.

PowerShell: the last five .NET Runtime 1026 events

Get-WinEvent -FilterHashtable @{ LogName='Application'; ProviderName='.NET Runtime'; Id=1026 } -MaxEvents 5 |
  Format-List TimeCreated, Message

• Same program every time? The problem belongs to that program. Go by the chooser table above.
• A program you never start? Updaters, tray tools and background services also run on .NET. The name tells you which one, and Fix 2 still applies.
• A different program each time? Go to Fix 4 and then Fix 6.

Fix 2. Update, repair or reinstall the program named in the event

15 to 30 minutesLow riskThe first Exception Info line names a missing file, a wrong version or an error in the program's own code.

Microsoft's example of event 1026 is a program that could not find one of its own files. A missing, damaged or mismatched program file is fixed only by putting the program's files back, and a code bug only by a newer version.

1. Look up the program file from the Application line. If you do not recognise it, right-click the program in Task Manager > Details next time it runs, or search the file name in File Explorer.
2. Check the program for an update: in its Help or About menu, or on the maker's website.
3. If no update exists, press Win + I and open Apps > Installed apps (Windows 10: Apps > Apps & features).
4. Select the three dots next to the program. If Modify or Repair is offered, run it first.
5. If that does not help, select Uninstall, restart the PC and install the newest version from the maker's own website.
6. Start the program and check Event Viewer for a new 1026 event.

Every way to remove a program, also from Control Panel: Uninstall a program or app in Windows A Store app has Repair and Reset buttons instead: How to repair or reset an app in Windows

Fix 3. Reset the program's damaged settings file

10 minutesLow riskThe event names ConfigurationErrorsException, or the program crashed for the first time after a power cut or a full disk.

A .NET Framework program reads its settings file the moment it starts. If that file is cut off or full of garbage, the program crashes before showing any window, and a reinstall often leaves the file in place.

Microsoft documents a ConfigurationErrorsException in event 1026 for one of its own services, wrapped in a TypeInitializationException. Most .NET Framework desktop programs keep per-user settings in a file named user.config under a folder named after the program's maker.

1. Close the program. In Task Manager, check that it no longer runs.
2. Press Win + R, type %LocalAppData% and press Enter.
3. Open the folder named after the program's maker. Inside, look for a folder that starts with the program file name, such as Program.exe_Url_ followed by random letters.
4. Rename that folder by adding .old at the end. Do not delete it.
5. Repeat steps 2 to 4 with %AppData%, because some programs keep the file there.
6. Start the program. It creates new settings with default values.

The older version of this guide renamed a file in %LocalAppData%\Microsoft_Corporation. That folder is the same kind of settings store for Microsoft programs, and renaming it works the same way. Changing the permissions of C:\Users, as that guide also said, is not needed and we removed it.

Fix 4. Repair .NET Framework and the Visual C++ runtimes

20 minutesLow riskSeveral .NET programs crash, or the event names DllNotFoundException or BadImageFormatException.

When many programs fail at once, the shared part they all use is the likely common factor. Many .NET programs also call native parts that need the Visual C++ runtimes, and a missing one shows up as DllNotFoundException.

1. Repair each Visual C++ entry. Right-click an entry and select Change, then select Repair in the window that opens. Do the same for every Microsoft Visual C++ entry.

   

2. Install the latest supported version. Download the latest Visual C++ v14 Redistributable from Microsoft: Visual C++ Redistributable latest supported downloads and run it. On a 64-bit PC install both X64 and X86, because 32-bit programs need the x86 package. On an ARM64 PC install ARM64. This one version serves programs built with Visual Studio 2017 to 2026.
3. Run the .NET Framework Repair Tool. Download the Microsoft .NET Framework Repair Tool and run NetFxRepairTool.exe. The wizard looks for setup problems, asks for your consent before it applies fixes, then repairs the installed .NET Framework versions. The tool is in English only.
4. Turn on .NET Framework 3.5 if a program asks for it. Select Start, search for Windows Features and open it. In Turn Windows features on or off, select the .NET Framework 3.5 (includes .NET 2.0 and 3.0) check box and select OK. Windows downloads the files, so stay online.

   

These steps were written for Windows 11 25H2 and 26H2, Windows 10 22H2. The full page with the other versions and what each result means: How to repair Microsoft Visual C++ Redistributable and .NET Framework

• Do not uninstall .NET Framework 4.8 or 4.8.1. It is part of Windows 10 and Windows 11. Unticking .NET Framework 4.8 Advanced Services in Windows Features, as older guides say, removes only ASP.NET and WCF parts and does not reinstall anything.
• Newer .NET programs (.NET 6, 8 and later) do not use .NET Framework. If the maker says the program needs such a version, install the matching .NET Desktop Runtime from dotnet.microsoft.com.
• Do not uninstall Visual C++ packages as the old guide said. Repair them, then add the latest supported version.

All steps, including Programs and Features and .NET Framework 3.5: How to repair Microsoft Visual C++ Redistributable and .NET Framework Missing Visual C++ files have their own guide: VCRUNTIME140_1.dll missing.

Fix 5. Give the program the access it needs

10 minutesLow riskThe event names UnauthorizedAccessException or IOException, or the program works when started as administrator.

UnauthorizedAccessException means Windows refused the program a file or folder. Common reasons are an old program that writes into its own install folder, and Controlled folder access in Windows Security blocking it.

1. Right-click the program's shortcut and select Run as administrator once, as a test.
2. If it now starts, check the maker's site for a newer version that does not need this.
3. Open Windows Security > Virus & threat protection and select Manage ransomware protection.
4. If Controlled folder access is on, open Block history and look for the program.
5. If it is listed, select Allow an app through Controlled folder access and add the program's .exe file. Protection stays on for every other app.
6. Start the program normally and check Event Viewer again.

If the maker says the program must run as administrator, make it permanent on the Compatibility tab: How to run a program as administrator or in compatibility mode

Fix 6. Find a program that interferes with a clean boot

20 minutesLow riskThe error type changes from crash to crash, or .NET Runtime events 1022 or 1023 appear near 1026.

Monitoring tools, overlays and some security programs load themselves into other processes. A clean boot starts Windows without them, so if the crash stops, one of them is the cause.

1. Do a clean boot with the steps in How to perform a clean boot in Windows: third-party services and startup apps off.
2. Start the program that crashed. If it works, turn half of the services back on and restart.
3. Repeat with smaller halves until the crash returns. The last group you turned on holds the culprit.
4. Update or remove that program, then return to a normal start.

Fix 7. Repair Windows system files with DISM and SFC

20 to 40 minutesNo riskWindows' own tools crash too, or Fixes 2 to 6 did not help and several programs are affected.

.NET Framework 4.8 is part of Windows 10 and 11, so damaged Windows files can damage it too. DISM restores the Windows image and SFC then replaces bad system files from it.

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 event 1026 keeps coming back: what to send and to whom

When the same Exception Info line comes back after a clean install, the bug is most likely inside the program. Only its maker can fix that, and they need the event text, not a description of the crash.

• The full text of event 1026. Copied with the Copy button in Fix 1, including all the "at" lines.
• The matching event 1000. Program version, fault offset and report ID help the maker match crashes.
• What you did. Starting the program, opening a certain file, printing, syncing.
• Your Windows version. Press Win + R and type winver.
• What you already tried. Reinstall, settings reset, clean boot.

How to keep .NET Runtime error 1026 from coming back

• Keep Windows updated. .NET Framework fixes arrive through Windows Update. Windows 10 left support on 14 October 2025, so a Windows 10 PC without extended updates no longer gets them.
• Update the program itself. Most 1026 crashes are fixed by the program's maker, not by Microsoft.
• Install from the maker only. Copied program folders and portable versions often miss files, which leads to FileNotFoundException.
• Keep free space on the system drive. A full disk can leave a settings file cut off, which leads to the crash in Fix 3.
• Shut down properly. A power cut while a program saves its settings is the most common way the settings file gets damaged.

One 1026 event for a tool you never use, logged once months ago, needs no action. Start looking when the same program logs it again and again, or when a program you need will not start.

Frequently asked questions

What is Event ID 1026 .NET Runtime error?

It is a crash report. When a program built on .NET hits an error its code does not handle, the .NET runtime ends the program and writes event 1026 from the source .NET Runtime into the Application log. The text always says "The process was terminated due to an unhandled exception." The useful parts are the Application line, which names the program, and the Exception Info line, which names the error type. The event itself is not something to repair: the cause is in the program it names.

Is .NET Runtime error 1026 a Windows bug or a virus?

Neither, in most cases. Microsoft's support articles show event 1026 as the record of a crash in one program, with the fix belonging to that program. It is not a sign of malware. If the Application line names a program you do not know and cannot find in Installed apps, check where the file lives and run a scan with Microsoft Defender, but treat that as a separate check. The error type in Exception Info, not the event number, decides what to do.

Why does .NET Runtime error 1026 come with KERNELBASE.dll and event 1000?

Because one crash writes two events. Event 1026 from .NET Runtime explains the .NET error. Event 1000 from Application Error records the same crash from Windows' side and names KERNELBASE.dll as the faulting module with the exception code 0xe0434352. Microsoft's own example shows this pair for a crash caused by a missing program file. KERNELBASE.dll is not damaged, so do not download or replace it. Read the Exception Info line of event 1026 instead.

What do .NET Runtime events 1022 and 1023 mean on Windows 11?

They are other events from the same source. We did not find a Microsoft page that documents them. In reports we read, event 1022 says a profiler failed to load, which points to a monitoring or diagnostic tool that hooks into .NET programs. Event 1023 says the process was terminated due to an internal error in the .NET Runtime. Both are a reason to try the clean boot in Fix 6, and for 1023 also the repairs in Fix 4 and Fix 7.

Is イベントID 1026 on Japanese Windows the same error?

Yes. On Japanese Windows, Event Viewer shows the same .NET Runtime event with ID 1026, only with translated labels. The event number, the source and the Exception Info lines with names such as System.IO.FileNotFoundException stay the same, because they come from .NET, not from the Windows language. The steps on this page apply. The program file name on the Application line tells you which program to fix.

How do I fix .NET Framework error 1026 in Sage 50 or QuickBooks?

Treat it like any other program: open event 1026 and read the Application and Exception Info lines (Fix 1). If the line names a missing file, use the program's own repair or reinstall it (Fix 2) after a backup of your company file. If it names a configuration error, reset its settings (Fix 3). We could not confirm a cause specific to Sage 50 or QuickBooks, so send the copied event text to the maker's support if the crash returns.

Can I ignore event 1026 if nothing seems to crash?

Often yes. Updaters, tray tools and background services also run on .NET, and when one of them crashes you see nothing but the event. Check the Application line. If it names a tool you do not use, remove that tool or leave it. If it names something you need, such as a backup or sync service, follow Fix 2, because that service has stopped working. A single old event needs no action.

Should I uninstall or turn off .NET Framework in Windows Features?

No. .NET Framework 4.8 and 4.8.1 are part of Windows 10 and Windows 11 and cannot be removed like a normal program. Unticking .NET Framework 4.8 Advanced Services only removes ASP.NET and WCF parts that most desktop programs do not use, so it does not reinstall anything. If you suspect damaged .NET files, run the .NET Framework Repair Tool and SFC instead (Fix 4 and Fix 7). Only .NET Framework 3.5 is turned on there when a program asks for it.

Is "error 1026" in other apps the same as event 1026?

Not always. This page is about event ID 1026 from the source .NET Runtime in Event Viewer. Other programs and streaming services use their own error 1026 with a different meaning, for example the Disney+ app. If you see error 1026 inside an app window and no .NET Runtime event at that time in the Application log, the steps here do not apply. Look up that app's own help page for its code.

Does .NET Runtime error 1026 look different on Windows 10 and Windows 11?

No. The event, its source, its level and its text are the same on Windows 10, Windows 11 and Windows Server, and so are the steps on this page. The menu paths differ only slightly: Installed apps on Windows 11 is Apps & features on Windows 10. Windows 10 left support on 14 October 2025, so .NET Framework fixes no longer reach a Windows 10 PC without extended updates.