Open File Explorer

Open DER on Windows OS

• Locate DER file in Windows Explorer and right-click on it.
• Look for the "Open with" menu option in the popup menu. If you open this menu you will see list of the applications which can open DER file.
• If there are no programs which can open the DER file are installed you will see "Open with..." button in the popup menu. Click on it.
• Dialog will open with Windows OS suggestion about what application can open DER file.
• If you do not see the application which correctly matches the file try to search the internet for one of the apps mentioned above or look for technical file description below. Each description have "Application name" in it which can open the DER file.
• If "Application name" is missing look for the "Windows Object" and "Executable command" fields because they typically contain application which can open DER file.

Open .der File and CERFile.

File Extension	.der
Description	Security Certificate
Sample File Name	[Sample File].der
Windows Object	CERFile
Executable Command To Open .der File	%SystemRoot%\system32\rundll32.exe cryptext.dll
Mime Type	CryptExtOpenCER %1
Links	How to open DER File instructions on extensionfile.net Placing it here to fix Firefox 2.0 layout links

Open .der File and CERFile.

File Extension	.der
Description	Security Certificate
Sample File Name	[Sample File].der
Windows Object	CERFile
Executable Command To Open .der File	C:\Windows\system32\rundll32.exe cryptext.dll,CryptExtOpenCER %1
Mime Type	application/x-x509-ca-cert
Links	How to open DER File instructions on extensionfile.net Placing it here to fix Firefox 2.0 layout links