access is denied

Hi dkinfa no,

Thank you for reaching out on the Microsoft Q&A forum. I understand how frustrating it can be to run into an “Access Denied” error, especially when it stops you from installing .NET Framework 3.5 and using your application.

The error code 0x80070005 usually means Windows is blocking the installation due to permission or security restrictions. Please follow the steps below in order to help resolve this issue:

Step 1: Confirm Administrator access

Please make sure you are logged in using an Administrator account.

• Open Settings > Accounts > Your Info
• You should see Administrator under your account name
• If not, please switch to an administrator account before continuing

Step 2: Temporarily disable Security software

Sometimes antivirus or security software prevents Windows from installing system components.

• Temporarily disable any third‑party antivirus or endpoint security tools
• If using Windows Security:
  • Open Windows Security > Virus & threat protection
  • Turn Real‑time protection off temporarily
• Re‑enable protection once installation is complete

*Disclaimer: Temporarily turn off real-time Microsoft Defender antivirus protection in Windows Security. However, keep in mind that if you do so, your device may be vulnerable to threats. So please turn it on immediately once issue fixed. 

Step 3: Repair Windows System Files

This checks and repairs Windows files and permissions that may be blocking installation.

1. Right‑click Start and select Command Prompt (Admin)
2. Run the following commands one by one:

sfc /scannow

After it completes, run:

DISM /Online /Cleanup-Image /RestoreHealth

1. Restart the computer when finished

Step 4: Install .NET Framework 3.5 using offline method

This method bypasses Windows Update and is often the most reliable.

• Download the Windows installation ISO that matches your Windows version
• Right‑click the ISO and select Mount
• Note the new drive letter (for example, D:)
• Open Command Prompt (Admin) and run:

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs

(Replace D: with the correct drive letter if different.)

• Restart the computer after installation completes.

Step 5: Retry your application

Once .NET Framework 3.5 is installed, please reopen your application and check if the issue is resolved.

If you encounter any errors during these steps, please let me know. I'm happy to assist further.

Thank you for your patience and cooperation.

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