File Extension/CER
alphabetical list of extensions

File extension .CER

File description

The file extension with the CER type is the one that supports the SSL certificate file format that is mostly utilized by the Web servers that is useful to verify the identity as well as the security of the site that is in question.

Normally, 3rd parties provide these SSL certificates to the websites and it mainly includes the Thawte, GlobalSign or VeriSign.

Description of the problem
If you have on your computer a .CER file that you cannot open, you are in exactly the same situation as thousands of other people who have similar problems with this or any other unknown file.

There may be several reasons why you cannot open the file with .CER extension. Directly on this website you can find a solution of the most common problem with the .CER file – that you do not have on your computer the appropriate program to open the file.
Solution
From the list below, select the appropriate program, install it and double click on the icon of a file that did not want to open - the problem with the .CER file extension should be solved. However, if this does not happen, go back to the website to learn about other possible causes of the error, which have been described at the bottom of the website.
Category
Web Files
Developer
N/A
Popularity
StarStarStarStarStar
File name: Internet Security Certificate
Programs that will open this file:
Windows
Windows
Adobe Acrobat Adobe Acrobat
Adobe Reader Adobe Reader
Internet Explorer Internet Explorer
Mozilla Firefox Mozilla Firefox
Mac OS
Mac OS
Adobe Reader Adobe Reader
Mozilla Firefox Mozilla Firefox
Safari Safari
Linux
Linux
Adobe Reader Adobe Reader
Mozilla Firefox Mozilla Firefox
Remember!
The .CER file extension can correspond to several not related file formats. If there is more than one file format with the .CER extension, you will probably find most of them at this website. Remember that you need to download a program to support a particular file type. So first look through the entire contents of the website to select a program to support just the file you have.

Other possible reasons why your .CER file does not want to open

In addition to the problem described above, i.e. the lack of the appropriate application to support the .CER file, there may be several reasons that cause problems with opening and operation of the data format:

1. Incorrect version of the installed application

A quite common problem is the lack of application in the appropriate version. Even if you have an application, with the help of which you should open the .CER file, you may have a problem with it because of its version. Perhaps in previous versions the application has not yet supported the .CER file, so download the update and check again.

2. Incorrect .CER file association with the program

If you have already installed the appropriate application, and it is the correct version, the file may not open correctly, because the operating system does not have information that this program supports the file. So you need to "show" which program the computer should use. To do this:

  • Right-click the .CER file
  • Go to the "Open with" - then "Choose default program ..."
  • Locate the appropriate application
  • Click "OK"

3. The file is corrupt

It also happens that the file you want to open is corrupt and therefore there is no such possibility. In this situation, you should find its different version, or ask a person from whom you got, to send it again.