Alex Ruben
How To Install Any FitGirl Game Successfully in 2025
This is one of those things that’s kinda weird but can mess up your whole day if you don’t handle it right. If you’ve ever tried to get a FitGirl repack working and ran into errors like ISDone.dll or Unarc.dll failing to load, you know how frustrating it can be. Sometimes Windows Security just freaks out and blocks those installation files, especially during unpacking or setup phases. So, this guide aims to lay out some proven steps that actually work, based on a bunch of trial and error, to help make the process smoother. What you’ll end up with is a game up and running without those annoying errors, saving some serious head-scratching and time.
How to Fix Common FitGirl Repack Installation Issues in Windows 10 & 11
Disable Real-Time Protection — Because Windows Security Can Be Overkill
This helps because Windows tends to quarantine or block large unpacking files or setup executables, thinking it’s malware. When the real-time protection is on, it sometimes corrupts or cancels parts of the installation, leading to errors like ISDone.dll or issues with unpackers. It applies when your install suddenly craps out right after starting, or during extraction, with cryptic DLL errors popping up. Expect the game to fail at unpacking or installing, or to crash out with ‘Bad Installation’ messages.
On some setups, you might have to disable it, then re-enable after install — don’t judge why it works, it just does. Be aware, though, that it leaves your system a bit more vulnerable, so don’t do this all the time, just during the install if you’re getting those errors.
- Open the Start Menu and type Windows Security, hit Enter.
- Head to Virus & Threat Protection.
- Click on Manage Settings.
- Toggle off Real-time Protection. You might see a warning, just confirm with Yes.
Start the Game Install — Watch for bumps
Now that your defenses are down a bit, it’s time to run the setup. Sometimes Windows prompts for admin rights or asks if you trust the source — that’s normal, just accept and move on. Choosing the right language, installing the game in a simple folder like C:\Games\GameName, and closing other apps can prevent conflicts.
- Locate your downloaded setup file, double-click it.
- Give it admin privileges if prompted — right-click > Run as administrator.
- Follow the prompts, choosing install directory without extra bloat unless needed.
Select Your Install Location and Optional Components
This part is kinda straightforward but worth doing right. Pick the folder where you want the game, preferably something simple like C:\Games\MyGame. On some systems, I’ve seen unchecking extra options like language packs or DirectX updates (unless you need those) speed things up.
- Click Next, then Install.
Finish Up and Avoid Errors Later
Once it’s done, don’t let it launch right away — leave that for after you tweak a couple more things. Uncheck the auto-launch box, hit Finish. That way, no files get opened or scanned immediately, which could cause hangs or partial installs.
Make Sure Windows Won’t Mess With Your Game Files
This is key since Windows Security can break your game if it sees new files as threats. Adding your game folder to exclusions has helped me avoid crashes or files disappearing mid-play.
- Open Windows Security again.
- Scroll to Add or Remove Exclusions, yeah, it’s under Virus & Threat Protection.
- Click Add an Exclusion, pick Folder.
- Navigate to your game folder — probably somewhere like
C:\Games\MyGame— and add it. - Once added, go back, re-enable Real-time Protection. Windows gets nervous, but sometimes it’s necessary.
Time to Launch and Play
Double-click the shortcut you made or the executable in the game folder. You might need to run as administrator, especially if you run into permissions issues.
- Follow any prompts, accept agreements, and if prompted to install DirectX or Visual C++ redistributables, do so.
Extra Tips & Common Pitfalls
Sometimes, the game still refuses to run or crashes. Here’s what else to check:
- Always download from a reputable source — shady files will just make things worse.
- Look for game patches or updates after install, sometimes they fix errors caused by incomplete unpacking.
- If all else fails, try verifying your system requirements or reinstall from scratch, because of course Windows has to make it harder than necessary.
Frequently Asked Questions
Why do I need to disable real-time protection?
Because Windows Security can block or corrupt files during the unpacking process, especially large ones, leading to errors like ISDone.dll or crashes during setup.
What if the installation keeps failing?
Check that you’re running as admin, have enough disk space, and that no background apps are interfering. Disabling real-time protection and adding your game folder to exclusions often helps.
Can I play without adding the folder to exclusions?
Yeah, technically, but it’s pretty likely Windows Security will flag or kill some files later, especially if you’re running something unpacked or modified. Exclusions save a headache later on.