It is a data file rather than a media or document file. It is a cache file used by Valve Steam which is the software package for downloading games.
Valve Steam was developed by Valve, and it uses files appended with .acf file extensions. The content stored in the data file includes details retrieved and referenced by the Valve Stream software whenever a user accessed associated features that have been integrated into the program.
The cache file saves information related to the downloaded software. It is also used for original game downloads as well as game updates. Data stored in the files also include the web locations of video game installers.
We hope we helped you solve the problem with the ACF file. If you do not know where you can download the application from our list, click on the link (which is the name of the program) - you will find more information there on the location where to download the secure setup version of the required application.
There can be more reasons which determine that you are not able to open the ACF file (apart from the lack of the proper application installed).
First - the ACF file may be incorrectly associated with the application installed to support it. In this case, you need to change this association by yourself. To do this, right-click on the ACF file that you want to edit, click "Open with" and then select the program from the list that you have installed. After this operation, the problems with opening the ACF file should be solved.
Second - the file you want to open can simply be damaged. Then, the best solution is to find a new version of given file, or download it again from the same source as before (maybe for some reason in the previous session the download of the ACF file has not been completed and it cannot be opened properly).
If you have additional information about the ACF file, we will be grateful if you share it with our users. To do this, use the form here and send us your information on ACF file.