A8S File

What are A8S files and how to open them

Are you having problems opening an A8S file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your A8S files.

What is an A8S file?

An .A8S file is an Atari800Win Plus Snapshot file.

An Atari800Win Plus Snapshot file records a complete saved-state of an Atari 8-bit machine under the Atari800Win Plus emulator. It is produced when a user chooses the emulator's Save State command (for example via the File → Save State → Normal menu). The file captures the exact moment of a running emulation, allowing later restoration of memory, processor state and currently-attached media so that the machine resumes from that point when loaded via Load State.

These snapshot files are written by Atari800Win Plus and by compatible emulators using the same format, and are read back by those tools to restore the emulated system's entire state. The .A8S file is not a disk image, nor a game ROM; it is not meant for distribution of games or programs, but as a local save of in-emulator progress, including cartridge or disk images currently attached. Different versions of the emulator may produce incompatible snapshot files, as internal state layout (memory banks, versioned hardware signatures, etc.) can change across releases.

Internally the file begins with the ASCII signature ATARI800 followed by a version or format byte.

How to open A8S files

Important: Different programs may use files with the A8S file extension for different purposes, so unless you are sure which format your A8S file is, you may need to try a few different programs.

While we have not verified the app ourselves yet, our users have suggested a single A8S opener which you will find listed below.

Last updated: August 16, 2026

Various apps that use files with this extension

These apps are known to open certain types of A8S files. Remember, different programs may use A8S files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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