Shimeji on Mac: What Works and How to Open It

1. Why Shimeji Won't Open on a Mac

Kilkakon's page describes shimeji as little desktop companions that run around your computer screen, with characters made by artists all over the world. Kilkakon's version builds on the Shimeji-ee group's project, which was based on work by Yuki Yamada of Group Finity.

Here's the catch for Mac owners. Kilkakon's page says Shimeji requires Java and runs only on Windows. If you grabbed that download on a MacBook and it won't run, that's likely why.

Mac ports do exist, though. The next section has three of them.

2. Three Ways to Run Shimeji on a Mac

The cells come from each project's own pages, as of October 2026.

ShimejiEE cross-platform

Its README calls it a fork of Kilkakon's Shimeji-ee that brings in the earlier shimeji4mac work. ShimejiEE cross-platform's README says to download the mac-jre version for macOS and click the file named ShimejiEE-launcher.

Its releases page lists v2.1.0, published in October 2022, as the latest release. The README says releases aren't updated often and suggests building from source for the newest version. That's a long gap, so check the releases page for anything newer before you download.

Shijima

Shijima's itch.io page says it brings shimeji desktop pets to macOS, Linux and Windows, and installs shimeji straight from zip, rar and 7z archives. The same page says you don't need Java. Shijima's site lists one macOS download for Shijima-Qt, its desktop app, built for arm64 (Apple silicon Macs).

Worth knowing before you pick it: Shijima-Qt's README says the desktop version was discontinued and archived, and that v0.1.0 has been its latest stable build for over a year. The download is still listed on its site. Shijima-Qt's README says it needs the Accessibility permission on macOS to find the frontmost window.

Shijima's itch.io page says you install the shimeji you want yourself, and names DeviantArt, Pixiv and Twitter as places to find them.

Shimeji Browser Extension

Its Chrome Web Store listing says the shimejis play around on the websites you visit, and that it works on desktop computers running Windows, Mac or ChromeOS. You add it to Chrome, and the shimejis play on the web pages you have open.

3. When macOS Won't Open It

The two desktop ports are downloads from outside the App Store, so macOS checks them before they run. These are Apple's general steps for any app like that. They aren't specific to any shimeji program.

For an app downloaded from the internet or directly from a developer, Apple says macOS checks the developer's Developer ID signature, and that by default macOS Catalina and later also require the software to be notarised. Apple says macOS asks for your approval before you open downloaded software for the first time.

If macOS cannot verify an app's developer and, in macOS Catalina and later, the app has not been notarised, Apple says macOS cannot confirm the app is free of malware.

Opening it anyway. Apple says that if you are certain an app comes from a trustworthy source and has not been tampered with, you may be able to temporarily override your Mac security settings to open it. After you try to open the app, open System Settings, click Privacy & Security, then scroll down and click Open Anyway. Apple says the warning prompt reappears, and if you are absolutely sure you want to open the app anyway, you can click Open.

The README covers what to do if macOS won't open the launcher because it's from an unidentified developer. Its steps use the older System Preferences and Security & privacy names. Apple's current page has the steps above, so go by those on a newer Mac.

4. Is Shimeji Safe?

We haven't installed any of these programs, so we can't vouch for one. What we can tell you is where the pieces come from.

Shimeji-ee and Shijima-Qt publish their code under a stated licence. Kilkakon's page calls Shimeji-ee an open source project. Shijima-Qt's GitHub page lists the GPL-3.0 licence.

Characters are another matter. Kilkakon's page says they're made by artists all over the world, and Shijima's page points to DeviantArt, Pixiv and Twitter for finding them. So packs come from many different makers. Get the program itself from the project's own page, linked in the sources below, and section 3 covers what macOS checks when you open it.

5. Where Nibbii Fits

Disclosure: Nibbii publishes this page.

Nibbii is a pixel pet that lives in your MacBook notch. It doesn't load shimeji characters; it comes with its own cast of 11 pets, and on a Mac with no notch it draws its own perch at the top of the screen. With Pro, it can also roam around your desktop.

Nibbii is a Mac app and requires macOS 15+. The base app is free to keep: one starter pet, two worlds, core care and play, simple essentials, and growth through Level 10. Pro lets you collect all 11 pets and 22 worlds as you play. Download it from nibbii.pet. It's signed with a Developer ID and notarised by Apple.

Nibbii is strictly for people aged 13+.

Setup is on the MacBook notch pet page. For other pet apps on the Mac, see desktop pets for Mac and Desktop Goose on Mac.

6. Questions People Ask

7. Sources

• Facts about Nibbii come from this site.
• Facts about Shimeji-ee (Kilkakon) come from kilkakon.com, as of October 2026.
• Facts about ShimejiEE cross-platform come from its GitHub page, as of October 2026.
• Facts about Shijima come from getshijima.app, as of October 2026.
• Facts about Shimeji Browser Extension come from its Chrome Web Store listing, as of October 2026.
• Shijima's other pages: its itch.io page and the Shijima-Qt GitHub page.
• ShimejiEE cross-platform's releases page.
• Apple's Open apps safely on your Mac, which Apple dates June 2026.

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