Tips to open PAC file

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

PAC file extension

File Name Proxy Auto-Config Format
File Developer Netscape
File Category Web Files

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

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

What is PAC file?

The file with the extension PAC is the Web Files file type. It was designed by Netscape. Web Files consists of 303 similar files. Proxy Auto-Config Format appears on 3 operating systems as a functional file. Although it can be found with greater or lesser success on any operating system, it will only be useful on Linux, Mac OS, Windows. The Safari application is recommended to open the file. It was released by Apple, Inc.. This file type can also be opened by 4 other programs. The Mozilla Firefox, Microsoft Internet Explorer programs will also handle the file when the Safari program does not fulfill its role.

How to open PAC file?

An often recurring problem with Proxy Auto-Config Format is that PAC is not associated with the correct program file. This causes the file PAC to open by system applications not designed for this purpose, or to display a message that there is no associated program. How to solve such a problem?

The first thing you should do is just "doubleclick" on the PAC 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

In this case, you should first verify that the Safari application is installed on the computer. The easiest method is to use the system search engine by entering the program name Safari in it. In the absence of an appropriate program, its installation in the vast majority of cases will fix the problem. Below you will find a list of applications that support PAC files.

Step 2. Create association of Safari with PAC files

If the application is or has been freshly installed, but the PAC file still does not use the Safari program, it means no association. The association can be created using the drop-down list available by right-clicking on the file and selecting 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 PAC file.

Step 3. Update Safari to the latest version

If, however, after binding Safari with Proxy Auto-Config Format there were still problems, you should update the program to the latest version. Some applications allow you to update from the program level, and for others you need to download the installer from the Apple, Inc. page and install.

Step 4. Check for the following problems with the PAC 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. This is most often caused by a problem while downloading the PAC file. 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. Some antivirus vendors also provide free online scanners. For the best results, we will scan the entire operating system, not just our PAC file. As a result of the scan, sometimes it is not possible to recover PAC files, which are deleted if there is a backup of this file, then after restoring it, it must also be scanned.
Older version of PAC 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. Depending on the type of file, it is necessary to repair it accordingly. Some programs offer the option of recovering data from damaged PAC files. The easiest way to restore the file is from a backup or by contacting Netscape, but this one can be expensive. Not all damage can be reversed.
The program indicates that the file is encrypted or corrupted. The encrypted PAC 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.
The operating system protects files in some locations (e.g. the root of the system partition) against unauthorized access. These directories are write-protected to them and it's very hard to fix this problem. If possible, you can try to move the PAC file to another location.
This problem usually affects more complex files. In this case, the PAC file is blocked by the first application to open it. Closing other programs should help. Sometimes it is necessary to wait a while before referencing the PAC file again. However, some background programs may block the PAC file while scanning. If this does not work either, restart the device.