Tips to open DER file

Can't open the DER file? You are not the only one. Thousands of users face similar problems every day. Below you will find tips on how to open DER files as well as a list of programs that support DER files.

DER file extension

File Name DER Certificate Format
File Category Web Files

The DER file is supported on 3 operating systems. Depending on your operating system, you may need different software to handle the DER files. Below is a summary of the number of programs that support and open the DER file on each system platform.

Operating systems
  • 3
  • 2
  • 1
  • 0
  • 0
  • 0

What is DER file?

The file with the extension DER is the Web Files file type. Additionally, the Web Files category contains 303 of other files. DER Certificate Format is supported by 3 operating systems. The file will work on Linux, Mac OS, Windows systems, unfortunately not on others. The main program that supports this format is Safari. This was created by Apple, Inc.. This file type can also be opened by 5 other programs. Opera, Mozilla Firefox, Microsoft Internet Explorer will apply when it is not possible to use Safari.

How to open DER file?

The most common problem when using DER Certificate Format is that a specific DER is not associated with the program. This is manifested by the fact that DER files open in unusual applications or do not have an assigned program. This can be quickly resolved by following the instructions below.

The first thing you should do is just "doubleclick" on the DER file icon you want to open. If the operating system has an appropriate application to support it and there is also an association between the file and the program, the file should be opened.

Step 1. Install Safari

The first step is to check if the computer has the Safari program installed. This can be achieved by typing Safari into the operating system search engine. In the absence of an appropriate program, its installation in the vast majority of cases will fix the problem. Later in this article you will find a list of programs that can open DER files.

Step 2. Create association of Safari with DER files

If the application is or has been freshly installed, but the DER file still does not use the Safari program, it means no association. It is most convenient to call the context menu with the right mouse button and select Properties. The displayed window will contain information about the program that supports this type of file. Changes can be made using the "Change" button. If there is no software on the list, simply select "Browse" and manually select the directory where the application is installed. The "always use the selected program ..." field will set the Safari application as the default for handling the DER file.

Step 3. Update Safari to the latest version

If, however, after binding Safari with DER Certificate Format there were still problems, you should update the program to the latest version. This can be done using the application (if it provides such options) or from the Apple, Inc. website and install the latest version.

Step 4. Check for the following problems with the DER file

The problem may also be with the file itself if the above steps don't work. This could be due to the file itself, the cleanest issues are:

Very often, the file may be size 0 or incomplete. Usually this applies to DER files downloaded from the Internet in case the download did not finish properly. The file should be downloaded again, making sure that the process has finished correctly.
The most common cause here is computer viruses. A virus scan using an up-to-date antivirus program should fix the problem. If this is not possible, you can use the online scanner. For the best results, we will scan the entire operating system, not just our DER file. Sometimes virus-infected DER files cannot be recovered, so make a backup in advance.
Older version of DER file may not always be supported by the latest software version. These problems are known and are often very easy to fix using the software developers's website.
The file may be corrupted in a number of ways. The repair method must be adapted to the type of file and damage. Some programs offer the option of recovering data from damaged DER files. You can restore the file from a backup or use N/A help.
When reading, a message appears that the file was encrypted or corrupted. The encrypted DER files can be used by the device on which they were encrypted, on any other device it is required to have the appropriate cryptographic key and decrypt the file before its recovery.
Some of the system directories are excluded from modification. The problem is only writing to the file, not reading it. Copying the DER file to another location will fix the problem.
This problem usually affects more complex files. Some file types can only be opened in one program at a time. Just close unnecessary programs. Sometimes you have to wait for the session to the file DER to close. Some anti-virus or backup software may occupy the DER file for a certain period of time. If the problem persists, restart the machine.