A .PAC file, also known as the Proxy Auto-Config file, is a configuration file that is used by the web browser for automating the proxy server connection setting. The PAC file contains a single function written in Java script to specify the mode of connection to be established by the web browser to access the specified URL. The mode of connection specified by the PAC file can choose either a direct mode to access the URL directly or through a proxy server. Further, the PAC file is created and edited using a simple text editor supported on Windows and MAC OS.
The list that follows enumerates programs compatible with PAC files, divided into 3 categories based on operating system on which they are available. Files with PAC extension, just like any other file formats, can be found on any operating system. The files in question may be transferred to other devices, be it mobile or stationary, yet not all systems may be capable of properly handling such files.
There can be multiple causes why you have problems with opening PAC files on given system. Fortunately, most common problems with PAC files can be solved without in-depth IT knowledge, and most importantly, in a matter of minutes. The list below will guide you through the process of addressing the encountered problem.
The main and most frequent cause precluding users form opening PAC files is that no program that can handle PAC files is installed on user’s system. This one is an easy one. Select Microsoft Internet Explorer or one of the recommended programs (for example, Mozilla Firefox, Safari) and download it from appropriate source and install on your system. Above you will find a complete listing of programs that support PAC files, classified according to system platforms for which they are available. If you want to download Microsoft Internet Explorer installer in the most secured manner, we suggest you visit Microsoft Corporation website and download from their official repositories.
If the problems with opening PAC files still occur even after installing Microsoft Internet Explorer, it is possible that you have an outdated version of the software. Check the developer’s website whether a newer version of Microsoft Internet Explorer is available. Software developers may implement support for more modern file formats in updated versions of their products. If you have an older version of Microsoft Internet Explorer installed, it may not support PAC format. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using Microsoft Internet Explorer.
If the issue has not been solved in the previous step, you should associate PAC files with latest version of Microsoft Internet Explorer you have installed on your device. The process of associating file formats with default application may differ in details depending on platform, but the basic procedure is very similar.
Change the default application in Windows
Change the default application in Mac OS
You closely followed the steps listed in points 1-3, but the problem is still present? You should check whether the file is a proper PAC file. It is probable that the file is corrupted and thus cannot be accessed.
If the PAC is indeed infected, it is possible that the malware is blocking it from opening. Scan the PAC file as well as your computer for malware or viruses. If the scanner detected that the PAC file is unsafe, proceed as instructed by the antivirus program to neutralize the threat.
If the PAC file was sent to you by someone else, ask this person to resend the file to you. It is possible that the file has not been properly copied to a data storage and is incomplete and therefore cannot be opened. When downloading the file with PAC extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.
There is a possibility that the file in question can only be accessed by users with sufficient system privileges. Switch to an account that has required privileges and try opening the Proxy Auto-Config Format file again.
If the systems has insufficient resources to open PAC files, try closing all currently running applications and try again.
Regularly updated system, drivers, and programs keep your computer secure. This may also prevent problems with Proxy Auto-Config Format files. It may be the case that the PAC files work properly with updated software that addresses some system bugs.
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