.BKM file extension
To open .BKM files on Windows, install and run BizHawk (from the official BizHawk project).
To open a .BKM file, use the BizHawk emulator on a desktop OS and load it as a movie/input recording. If the file won’t open, you may be using a newer workflow that expects .BK2 instead of the older .BKM format.
Last updated: April 29, 2026 · Reviewed by Julian Stricker
Open on your device
Choose your operating system for a dedicated step-by-step opening guide.
How to open .BKM files
Use these platform-specific instructions to open .BKM files safely.
Windows
- Install and run BizHawk (from the official BizHawk project).
- In BizHawk, use the movie feature to open/play the movie file and select your .BKM file.
- If the movie won’t load, confirm you’re using a BizHawk setup that supports legacy .BKM, or obtain a .BK2 version of the movie if that’s what your workflow expects.
Mac
- Use BizHawk on macOS if available in your setup; otherwise transfer the .BKM to a Windows/Linux machine with BizHawk for playback.
- If you only need to inspect the file, open it in a plain-text editor (it is UTF-8 text).
Linux
- Install and run BizHawk (from the official BizHawk project).
- Use BizHawk’s movie playback/open feature to load the .BKM file.
- If playback fails, try a BizHawk version/workflow known to handle legacy .BKM, or use a .BK2 equivalent when available.
iOS
- iOS does not commonly support BizHawk movie playback; transfer the .BKM to a desktop system with BizHawk, or open it only for viewing in a text-capable app (UTF-8).
Android
- Android does not commonly support BizHawk movie playback; transfer the .BKM to a desktop system with BizHawk, or open it only for viewing in a text-capable app (UTF-8).
Security notes
- .BKM is a text-based format, not an executable, but treat it as untrusted input: opening it in an emulator still means parsing external data, which can expose you to bugs in the parser.
- Prefer opening .BKM files with the official BizHawk builds from the BizHawk project, and avoid unknown “converter” utilities from untrusted sources.
- If you only need to inspect contents, open .BKM in a plain-text editor (UTF-8) rather than running it through tools you don’t trust.
Recommended antivirus software
Scan files before opening them. These antivirus tools help protect against malware and viruses.
Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.
NortonNorton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.
We may earn a commission when you use affiliate links. This supports our free file extension guides.
Can't open this file?
These are the most common causes and fixes when .BKM files fail to open.
Common reasons
- The .BKM file won’t open or play back in BizHawk
- The file opens as “garbled text” or with wrong characters
- Accidental edits break the movie
Fix steps
- Verify the file is a BizHawk movie (.BKM) and not a different unrelated format using the same extension.
- Try loading the movie in BizHawk using the movie open/playback feature; if you’re using a setup that expects .BK2, obtain a .BK2 version or use a BizHawk configuration that supports legacy .BKM handling.
- Ensure you have the correct game/ROM and compatible emulator core settings expected by the movie.
OS-specific troubleshooting
What is a .BKM file?
A .BKM file is BizHawk’s original movie format for recording emulator input, documented as a UTF-8 text file with structured fields. It was obsoleted by BizHawk’s newer .BK2 movie format (the replacement format for later versions). Because it’s plain text, you can also inspect it in a text editor, but editing may break playback if the structure is altered.
Background
In the BizHawk emulator community, “movie” files capture controller inputs and related metadata so a run can be replayed deterministically. The .BKM format is BizHawk’s original movie format, documented as a UTF-8 text file with a defined structure and fields (e.g., header/metadata and input log lines).
This format became legacy when BizHawk introduced .BK2 as the newer movie format. As a result, you’ll still encounter .BKM files when working with older projects, legacy TAS submissions, or archives that predate the switch.
Practically, .BKM is most useful inside BizHawk for movie playback/editing workflows. Outside of BizHawk, the main “opening” experience is reading it as text to understand metadata or verify contents; it is not a general-purpose media/video file.
Common MIME types: application/vnd.nervana
Further reading
Authoritative resources for more details on the .BKM format.
Common .BKM issues
The .BKM file won’t open or play back in BizHawk
.BKM is a legacy movie format and may not be the expected format for your current BizHawk workflow (which uses .BK2 in newer versions). Playback can also fail if the movie depends on a specific core/game setup.
- Verify the file is a BizHawk movie (.BKM) and not a different unrelated format using the same extension.
- Try loading the movie in BizHawk using the movie open/playback feature; if you’re using a setup that expects .BK2, obtain a .BK2 version or use a BizHawk configuration that supports legacy .BKM handling.
- Ensure you have the correct game/ROM and compatible emulator core settings expected by the movie.
The file opens as “garbled text” or with wrong characters
The .BKM format is documented as UTF-8 text; opening it with the wrong encoding can make it look corrupted.
- Open the file in a text editor that lets you choose encoding and select UTF-8.
- Avoid saving the file in a different encoding if you plan to use it again in BizHawk.
Accidental edits break the movie
Because .BKM is structured text, small changes can invalidate expected fields or input log formatting and stop a movie from replaying correctly.
- Restore the original from a backup or re-download the file from its source.
- If you must edit, make a copy first and follow the documented field/log structure for .BKM.
FAQ
Is a .BKM file a video?
No. In the BizHawk context, .BKM is a “movie” meaning recorded controller inputs and metadata for deterministic replay in the emulator, not a rendered video.
Why do people mention .BK2 instead of .BKM?
BizHawk replaced the older .BKM movie format with the newer .BK2 format; .BKM is considered legacy/obsolete in later BizHawk versions.
Can I convert .BKM to .BK2 by renaming the extension?
No. Renaming doesn’t change the underlying format. If you need .BK2, use BizHawk’s movie workflow or a method documented by the BizHawk/TAS community for working with legacy movies.
What MIME type should I use for .BKM?
There is no .BKM-specific MIME type in the provided sources. The only referenced media type is IANA’s application/vnd.nervana, but the sources do not link it to .BKM specifically.
Similar file extensions
Compare related formats in the same category to find the right tool faster.