A01 file: How can I open a .A01 file?
The table below provides useful information about the .a01 file extension. It answers questions such as:
- What is the .a01 file?
- What program do I need to open a .a01 file?
- How can the .a01 file be opened, edited or printed?
- How can I convert .a01 files to another format?
We hope you find this page helpful and a valuable resource.
✅ ARJ Compressed Archive

The ARJ file is an ARJ Compressed Archive. It is the native format of ARJ (dos) and WinARJ archiver. Like other archives, ARJ files are data containers, they store one or several files in the compressed form.
✅ ALZip Archive

The ALZ file is an ALZip Archive. The ALZ archive format from ESTsoft is specially designed for very large archives. There is no size limit on an ALZ archive like there is for ZIP files. So you can backup storage intensive files like raw video footage.
⚠ Be careful with .a01 files.
It's important to know that the .a01 file extension can be used by various programs, not just the ones you expect. This includes potentially harmful software or malware that might create .a01 files. Be cautious when dealing with .a01 files from unknown sources.
🚫 The .a01 file extension is often given incorrectly!
According to the searches on our site, these misspellings were the most common in the past year:
Is it possible that the filename extension is misspelled?
We found the following similar file extensions in our database:
🔴 Can't open a .a01 file?
When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:
Select an app to open this .a01 file
It means that the operating system does not have a default app associated with the .a01 file type. To resolve this issue and open the file, you can take the following steps:
- Right-click on the .a01 file. A context menu will appear.
- From the context menu, select Open with. Windows will display a list of recommended apps.
- If the desired app is listed, select it from the provided options.
- If you cannot find the appropriate app, you may need to install software that supports the specific file type.
If you don't know how to change the default app for the .a01 file, check the FAQ.
🔴 Can I change the extension of files?
Changing the filename extension of a file is not a good idea. The extension of a file serves as a hint to the operating system and various software programs about the type of data contained within the file. When you alter a file's extension, you essentially modify how software applications interpret and handle that file. Every file has a specific format, also known as its file type or file format. The problem is, changing the file extension does not change the file format.
If you have helpful information about the .a01 file extension, write to us.