PS2 BIOS Not Found: How to Fix It
The "PS2 BIOS not found" error almost always means the file is still zipped, sitting in a subfolder, renamed, or in the wrong place. Extract it, put it directly in the emulator's bios folder with its original name, and refresh the list.
The message stops every game from loading. The cause is usually small, and the fix takes a minute. Below are the exact errors and their fixes, most common first.
Quick fix for "BIOS not found"
Extract the file, place it directly in the bios folder, keep its name, and refresh.
- Extract the
.binfrom its.zipor.7z. The emulator cannot read an archive. - Move it directly into the
biosfolder, not a folder inside it. - Keep the original file name.
- In PCSX2, open Settings > BIOS, click Refresh List, and select it.
This clears the error for most people. The exact folder for each platform is on the install guide. If it still fails, work through the specific cases below.
The BIOS list is empty
The emulator is looking at a folder that has no valid BIOS in it.
The usual reason is that the emulator points at the wrong folder. Sometimes the file is still zipped or buried in a subfolder. Use the Browse button to point it at the exact folder that holds the .bin, then click Refresh List. On Android, you do not browse folders by hand. Open the app and run its BIOS import again instead.
"Invalid BIOS" or a corrupted file
The file is incomplete or has been tampered with. Check its fingerprint.
Compare the file's SHA-256 or MD5 to a known-good value, the way our PS2 BIOS files explained page shows. A failed match means the file is bad, usually from a broken download or a damaged archive. Replace it with a verified download or dump a fresh copy from your own console.
Black screen when a game starts
If the black screen appears when you load a game, this is usually a region mismatch, not a missing BIOS.
Switch to the BIOS that matches the game's region and load it again. English games want the USA BIOS, and which PS2 BIOS to use covers the rest. There is a second case worth separating. Sometimes the black screen appears at the emulator itself, before any game loads. That means the BIOS is missing or wrong. Go back to the quick fix at the top.
Wrong region or wrong language
The selected BIOS does not match your games.
If a game boots but shows the wrong language, or refuses to start, you probably picked a BIOS from the wrong region. Select the matching one in the BIOS list. For most players that is the USA BIOS, and you can keep more than one region on hand and switch as needed.
"Not a PS2 BIOS" or the file is rejected
You likely have a PS1 BIOS or a file that is not a BIOS at all.
PS2 emulation needs a PS2 BIOS. A PlayStation 1 BIOS will not work for PS2 games. Neither will a random file renamed to look like one. Make sure the file is the PS2 model file, such as one named after an SCPH model. If you are unsure what you have, the files explained page describes each real BIOS file.
Android: BIOS not detected (NetherSX2 or AetherSX2)
Re-import the BIOS through the app, not the file system.
Open the app's BIOS or System settings and add the file again. These apps manage the file for you, so moving it by hand rarely works. Remember that AetherSX2 is no longer updated, so if you keep hitting problems, NetherSX2 is the better choice. The PS2 BIOS for Android page has the full setup.
Steam Deck: the EmuDeck BIOS checker shows red
The file is missing, misnamed, or fails its checksum.
Put the file in the Emulation/bios folder, keep its original name, and run the BIOS Checker again. A red result after that points to a bad file, so verify its checksum and replace it if it does not match.
RetroArch: the core cannot find the BIOS
The file is not in the folder RetroArch reads.
Place it in system/pcsx2/bios, with pcsx2 and bios in lowercase. If you are not sure where the system folder is, check Settings > Directory > System/BIOS in RetroArch, then restart the core.
When it is not the BIOS at all
If the BIOS is detected and a game still fails, the problem is somewhere else.
At that point the BIOS has done its job. The cause is usually the game file, the graphics settings, or the specific title. That is outside a BIOS fix. Still, it helps to know the BIOS is fine once it shows in the list and a game reaches the boot animation.
Still stuck? Start fresh
If nothing above works, the file itself is the suspect.
Delete it and get a clean one. Dump a fresh copy from your console with our dump guide, or grab a verified file from the PS2 BIOS download hub. A clean, checksum-matched file rules out the most stubborn errors.
Quick reference: error to fix
| Error | Likely cause | Fix |
|---|---|---|
| BIOS not found | Zipped, nested, renamed, or wrong folder | Extract, place in bios folder, refresh |
| BIOS list empty | Emulator points at the wrong folder | Browse to the folder with the .bin |
| Invalid or corrupted | Bad download or damaged file | Verify checksum, then replace or re-dump |
| Black screen on game load | Region mismatch | Match the BIOS region |
| Not a PS2 BIOS | PS1 BIOS or wrong file | Use a real PS2 model file |
| Not detected on Android | File not imported in the app | Re-import via app settings |
| EmuDeck checker red | Missing, misnamed, or bad file | Put in Emulation/bios, re-check |
| RetroArch cannot find it | Wrong system subfolder | Use system/pcsx2/bios |
Frequently asked questions
Why does PCSX2 say no BIOS found?
bios folder with its original name, and click Refresh List.