OPF File Extension

What is OPF file?

File with .OPF extension stores digital publication metadata saved in text format based on XML standard. OPF format conforms to Open Packaging Format standard, which is a part of EPUB ebook specification. OPF was released in 3 versions and is now maintained by W3C (formerly by IDPF). OPF files store such information as:

• Title,
• Author,
• Language,
• Publication ID – usually ISBN identifier,
• Reading order,
• Navigation method,
• Formatting,
• Pointers to optional elements,
• Description and references to all parts of given publication.

OPF files are a part of a larger file archive package that constitutes an EPUB file. OPF files required that a related NCX file, which contains table od contents, be present in the publication package. Latest versions of OPF standard supports backward compatibility, however, a ebook reader or application that supports OPF version 3 may ignore some data used by OPF files version 1 or 2. EPUB package also contains an OPS file, OCF file, which describes the contents of given container, XHTML formatting file, and CSS, SVG or other image files. OPF files can be accessed by opening EPUB archive. OPF filename is typically content.opf, but it can be basically anything as META-INF file in EPUB package contains references to all files in the package.

Programs which support OPF file extension

Below you will find an index of software programs that can be used to open OPF files divided into 3 categories according to system platform supported. Files with OPF 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.

Updated: 03/13/2022

How to open file with OPF extension?

Being unable to open files with OPF extension can be have various origins. Fortunately, most common problems with OPF files can be solved without in-depth IT knowledge, and most importantly, in a matter of minutes. The following is a list of guidelines that will help you identify and solve file-related problems.

Step 1. Install Adobe InDesign software

The most common reason for such problems is the lack of proper applications that supports OPF files installed on the system. The most obvious solution is to download and install Adobe InDesign or one to the listed programs: Calibre, FBReader, Mobipocket eBook Creator. The full list of programs grouped by operating systems can be found above. The safest method of downloading Adobe InDesign installed is by going to developer’s website (Adobe Systems Incorporated) and downloading the software using provided links.

Step 2. Update Adobe InDesign to the latest version

If you already have Adobe InDesign installed on your systems and OPF files are still not opened properly, check if you have the latest version of the software. Software developers may implement support for more modern file formats in updated versions of their products. This can be one of the causes why OPF files are not compatible with Adobe InDesign. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using Adobe InDesign.

Step 3. Set the default application to open OPF files to Adobe InDesign

If you have the latest version of Adobe InDesign installed and the problem persists, select it as the default program to be used to manage OPF on your device. The method is quite simple and varies little across operating systems.

Selecting the first-choice application in Windows

• Right-click the OPF file and choose Open with option
• Click Choose another app and then select More apps option
• Finally select Look for another app on this PC, point to the folder where Adobe InDesign is installed, check the Always use this app to open OPF files box and conform your selection by clicking OK button

Selecting the first-choice application in Mac OS

• Right-click the OPF file and select Information
• Open the Open with section by clicking its name
• From the list choose the appropriate program and confirm by clicking Change for all....
• A message window should appear informing that This change will be applied to all files with OPF extension. By clicking Continue you confirm your selection.

Step 4. Ensure that the OPF file is complete and free of errors

Should the problem still occur after following steps 1-3, check if the OPF file is valid. Problems with opening the file may arise due to various reasons.

1. Check the OPF file for viruses or malware

If the OPF is indeed infected, it is possible that the malware is blocking it from opening. It is advised to scan the system for viruses and malware as soon as possible or use an online antivirus scanner. If the OPF file is indeed infected follow the instructions below.

2. Verify that the OPF file’s structure is intact

If you obtained the problematic OPF file from a third party, ask them to supply you with another copy. The file might have been copied erroneously and the data lost integrity, which precludes from accessing the file. It could happen the the download process of file with OPF extension was interrupted and the file data is defective. Download the file again from the same source.

3. Check if the user that you are logged as has administrative privileges.

Some files require elevated access rights to open them. Log out of your current account and log in to an account with sufficient access privileges. Then open the Open Packaging Format file.

4. Make sure that the system has sufficient resources to run Adobe InDesign

If the systems has insufficient resources to open OPF files, try closing all currently running applications and try again.

5. Check if you have the latest updates to the operating system and drivers

Latest versions of programs and drivers may help you solve problems with Open Packaging Format files and ensure security of your device and operating system. It is possible that one of the available system or driver updates may solve the problems with OPF files affecting older versions of given software.

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