All about 120 Files

The 120 file type is primarily associated with CCH ProSystem fx.

120	File extension: 120
	File type:	Data file

What is a 120 file

120 files mostly belong to CCH ProSystem fx. Overview: The *.120 file uses one of two specialized internal formats.

CCH Compound Document: This variant is a proprietary tax file produced by CCH ProSystem fx. It stores structured tax data in a compound format. Use the proprietary tax software to view and work with these files.

IMS Firmware Image: This variant is a firmware or system file. It is used in environments like 120-DOS and may appear as part of a Lotus Domino Server update. It is designed for system or firmware operations and should not be edited manually.

FilExt.com note: Identify which version you have to choose the correct viewing tool.
Files with the extension 120 are often also jpg images or pdf documents, but zip compressed archives or medical images such as DICOM are also common. Use the Online 120 File Viewer on this page to find out the file format being used, and to view your 120 file.

How to open a 120 file

You need a suitable software like CCH ProSystem fx to open a 120 file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your 120 file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a 120 file directly in the browser:. Just drag the file onto this browser window and drop it.

Online 120 Text Viewer

Choose your .120 file to analyze

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Online File Viewer

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120 file format:

The file format determines how the data is stored in the file. A file format is determined by the file extension and signature, so JPEG images have the extension .jpg and the first bytes in the file are ÿØÿ. If the file extension does not match the file format, double-clicking on the file will cause an error upon opening. When there is a problem with a file, the first step to solving it is to determine the file format. Our evaluation of the 120 files is as follows:

The 120 file extension is rarely used and includes many different file formats. The following file formats are most commonly found in 120 files:

• 15% of all 120 files start with the magic bytes CCH's Compound, v 2.00 @, which are always the first bytes of this file format. These files contain neither text nor words, but only data. 120 files can be up to 3 MB in size, but are often around 670 KB - 1 MB. The following keywords are characteristic: CCH's Compound, v 2.00 @ and DiagnosticFile. Files like these are sometimes connected to person-related data.
• 15% of all 120 files start with the bytes 11 00 00 9C 90 02 00 D6, which are crucial for this file format. The content consists of illegible binary data, which can only be read and interpreted by the associated programs. The average file size is 33 MB with most files being between 16 MB and 33 MB in size. A common filename is E7C77IMS.120.

All other 120 files (70%) have no consistent format, the following 3 formats exist: MATAHARI. If you want to find out what your 120 file contains, drag and drop it onto this page.