How to Install and Run Fleasion

Getting Fleasion running takes about five minutes: download our standalone build, run it as administrator, open the Dashboard from the tray, and launch Roblox through it. No Python, no installer. We wrote this guide to cover the whole thing on Windows, macOS and Linux, and — because we answer these in Discord constantly — to fix the handful of errors people actually hit. It ends with a clean uninstall.

Before you start

Fleasion runs on Windows 10 or 11, macOS (Intel and Apple Silicon both work), and Linux via the Sober Flatpak Roblox client. You don't need Python for the standalone app — we bundle everything it needs — and you'll want Roblox installed too. The first launch asks you to approve a one-time setup, so give it a moment.

Step 1: Download Fleasion — from us, not a mirror

Grab the current standalone build from the official Fleasion site — that's our primary distribution point — or from our open-source GitHub Releases for fleasion/Fleasion as the backup. Those two are the only places we publish genuine builds.

We can't stress this enough: don't download Fleasion from mirror sites, "free/premium/cracked" pages, or links you can't trace back to the official site or repo. That's where fake, trojanized copies live, and they're the whole reason the "is Fleasion a virus?" panic exists. If a download doesn't come from the official site or our GitHub, don't run it — here's how the real thing behaves.

You don't need Python. The standalone .exe and the macOS app carry everything they need. Python only matters if you decide to build from source.

Step 2: Install and run on Windows

The build is portable — there's no traditional installer.

1. Move the downloaded Fleasion.exe into a normal folder like Documents. Running it straight out of Downloads can occasionally throw a DLL error (we fix that below).
2. Right-click it and choose "Run as administrator." We ask for elevated rights because the app has to manage the hosts file and bind local port 443 — and honestly, running as administrator is the fix for most setup hiccups, so make it a habit.
3. If Windows SmartScreen shows an "unknown publisher" warning, that's the normal reputation prompt for a small, unsigned app. Pick "More info → Run anyway" — but only if you got the file from us.

What the first launch does

The first time it runs, Fleasion does a one-time setup and then gets out of your way. It generates a local certificate and installs it into Roblox's trust store so the secure connection to our proxy works, shows a short welcome dialog explaining how the proxy works, and opens the Dashboard for you. After that it lives in your system tray (bottom-right of the taskbar). If the window ever vanishes, right-click the tray icon → Dashboard to bring it back, or left-click the icon to hide/show it.

This is the exact welcome you'll see the first time — it points you at the tray, reminds you to clear the cache after changes, and sums up how the proxy works in two lines. Hit OK and the Dashboard opens.

Step 3: Launch Roblox through Fleasion

For your changes to route through the proxy, start Roblox while Fleasion is running. Easiest way is the Roblox Player launch button inside Fleasion — then pick your game. Opening Roblox normally works too, as long as Fleasion is sitting in the tray with its proxy active. If Roblox throws a "critical settings" error, skip to that fix.

Making your changes apply: clear the cache

This is the step people miss most, so we'll flag it early. After you add or edit a rule, Roblox has to re-download the affected assets through the proxy — so your change only shows up after you clear the Roblox cache or restart Roblox.

We built this to be automatic if you want:

• Clear Cache on Launch (we recommend it) clears the cache every start.
• Auto Delete Cache on Exit cleans up when Roblox closes.
• Or clear it manually from the tray menu anytime.

Rule of thumb: you can't change assets mid-game. Exit Roblox, make your changes, relaunch.

Installing on macOS

Same idea, with one privileged helper:

1. Download the macOS build from our Releases page and open it.
2. On first launch, macOS asks you to approve a small root-owned helper we install. It owns local port 443, updates /etc/hosts, and patches Roblox's ssl/cacert.pem. It needs one admin approval; the dashboard itself always runs as your normal user.
3. We verify that helper-patched certificate before writing any hosts entries. If verification fails, the proxy won't start — reinstall the helper and try again.
4. Use the normal Roblox app bundle. We don't support AppleBlox on the macOS path.

On first launch we may also ask which browser is signed in to roblox.com, so account-aware features can read your Roblox login; choose "Always Allow" if you'd rather not approve it each time. You can change it later under Settings → Roblox Login.

Installing on Linux (Sober)

On Linux we target the Sober Flatpak Roblox client (org.vinegarhq.Sober):

1. Get the Linux build, or run from source with the uv package manager.
2. Install the desktop launcher once so it runs with the right privileges:

   uv run Fleasion --install-desktop-entry
   

   That copies the app into ~/.local/share/Fleasion and creates a Polkit-enabled launcher — proxy interception needs root to update /etc/hosts and bind port 443, handled through pkexec/Polkit.
3. If the GUI won't launch, install PortAudio for your distro. That's almost always the missing piece.

Building from source (optional)

Since Fleasion is open-source (GPL-3.0), you can build it yourself — handy if you want to see exactly what you're running:

git clone https://github.com/fleasion/Fleasion.git
cd fleasion
uv run Fleasion              # auto-installs dependencies and runs

# optional: compile a standalone Windows executable
uv run pyinstaller Fleasion.spec

# optional: build the native macOS app
./scripts/build_macos.sh

You'll want the uv package manager. On Apple Silicon, a universal build also needs Rosetta (softwareupdate --install-rosetta --agree-to-license).

Do you need Python to run Fleasion?

No — not for the standalone build. This one confuses people because Fleasion is written in Python, so some tutorials tell you to install it. Our packaged .exe and macOS app include everything. You only need Python (via uv) if you choose to build from source. Already have Python installed? Makes no difference to the standalone app.

What actually trips people up (our tally)

We went back through the same 32 community setup guides we've catalogued, and the surprise is that the two things creators stress most aren't errors at all:

Honest caveat: video guides skew toward setup, not troubleshooting — the DLL and "critical settings" errors show up more in our Discord than in tutorials, which is why we still cover them in full below. But the pattern holds: most "install problems" are really "I grabbed the wrong file" or "I thought I needed Python." Get those two right and you've skipped most of the trouble — which is exactly why this guide leads with them.

Fixing common install and launch problems

"DLL load failed" when Fleasion starts

Move Fleasion.exe into a different folder — Documents is a safe pick — and run it from there. Windows sometimes grabs a stray, incompatible DLL sitting in the same folder as the executable (common in a cluttered Downloads folder), and moving the app to a clean folder sidesteps it.

Roblox: "Unable to download or apply critical settings"

If Roblox shows "Unable to download or apply critical settings, check your internet connection" when you launch it through Fleasion, use the Microsoft Store version of Roblox:

1. Install Roblox from the Microsoft Store — you'll get the "Roblox Player" app (different from the standard installer).
2. Launch that Roblox Player as administrator.

That clears the error for nearly everyone who hits it. Make sure Fleasion is running in the tray first.

The Fleasion window doesn't appear

It's in the tray. Right-click the icon → Dashboard, or left-click to unhide the window. If nothing shows at all, close it fully and re-run as administrator.

My changes aren't applying

Roblox is serving a cached copy. Clear the cache or restart Roblox after any change, and turn on Clear Cache on Launch. Remember you can't edit assets in a match, and some effects (skyboxes) don't apply on every map.

Linux: the GUI won't launch

Install PortAudio for your distro, then start Fleasion again.

macOS: the proxy won't start

We refuse to start the proxy if we can't verify the helper-patched Roblox certificate. Re-approve/reinstall the root helper, confirm you're on the standard Roblox app (not AppleBlox), and try again.

An "autoupdate.py" popup or missing-file error

If you hit an error about autoupdate.py (more common on older builds), download that file, drop it into your Fleasion folder, and run it — that resolves it. Then relaunch Fleasion normally.

How to uninstall Fleasion completely

It's portable, so removing it is quick:

1. Press Win + R, type %localappdata%, press Enter.
2. Find the Fleasion folder and delete it.

That clears the app's data. Want it back later? Just download the latest build from our Releases page. (On macOS and Linux, remove the app bundle / the files under ~/.local/share/Fleasion and the installed helper/launcher.)

Frequently asked questions

How do I install Fleasion? Download our standalone build from the official GitHub Releases page, move the .exe to a normal folder like Documents, and run it as administrator. Right-click the tray icon for the Dashboard, then launch Roblox through Fleasion.

Do I need Python to run Fleasion? No. The standalone build bundles everything. Python (via uv) is only for building from source.

Why do I have to run Fleasion as administrator? It needs elevated rights to edit the hosts file and bind local port 443, which is how the proxy works. It also fixes most first-time setup issues.

How do I fix "DLL load failed"? Move Fleasion.exe out of Downloads into a clean folder like Documents, then run it there.

How do I fix Roblox's "Unable to download or apply critical settings" error? Install Roblox from the Microsoft Store (the "Roblox Player" app) and launch it as administrator, with Fleasion running in the tray.

How do I uninstall Fleasion? Open Run (Win + R), type %localappdata%, delete the Fleasion folder. Done.

Updated July 2026 — added the real first-launch welcome screenshot and a tally of what actually trips people up during setup.

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