Alex Ruben
How To Fix Common Installation Errors in FitGirl Games (ISDone.dll, Unarc.dll) – 2025 Setup Guide
If you’ve been trying to get FitGirl repacks up and running and keep running into errors—things like ISDone.dll issues, Unarc.dll errors, or the setup just freezes—you’re not alone. Sometimes Windows Security gets a bit too aggressive, or something about your system setup causes conflicts during installation. This guide walks through some real-world fixes—tried, tested, maybe a bit annoying—that should help you get past those roadblocks and actually enjoy your games. No promises, but these steps have helped others, and they might just do the same for you.
How to Fix FitGirl Installation Errors in Windows
Disable Windows Security Temporarily
First, Windows Security has this tendency to block or interfere with game installers, especially homemade repacks or modified setup files. Turning off real-time protection, though not the safest move long-term, can stop it from throwing random errors mid-install. Why it helps? Because sometimes Windows treats these setup files as suspicious, even if they’re safe. When to do this? When errors pop up right as the installer starts or during unpacking. You can expect smoother installs without interruptions. Just a heads up: on some setups, this only fixes it temporarily, so re-enable protection afterward.
- Press Windows and type Windows Security, open it.
- Navigate to Virus & threat protection.
- Click on Manage settings (under Virus & threat protection settings).
- Switch off Real-time protection. Confirm with Yes if prompted.
Start the Installation with Elevated Rights & Compatibility Mode
This can be a lifesaver if the installer is getting stuck, failing to write files, or throwing DLL errors. Running as administrator ensures the setup has all the permissions it needs. Also, setting compatibility mode to an older Windows version (like Windows 7 or 8) sometimes helps, especially with older repacks. Why bother? Because Windows might block certain actions, which can cause errors. When you do this, expect the installer to run smoother, especially on newer systems.
- Right-click on the setup file.
- Select Properties.
- Go to the Compatibility tab.
- Check Run this program in compatibility mode for, then choose Windows 7 or 8.
- Also, check Run this program as administrator.
- Click Apply, then OK.
Clean Temporary Files and Disk Space
Sometimes, leftover temp files or insufficient disk space cause unpacking issues or install hangs. Clearing out temp folders can alleviate that. Also, make sure your drive has enough free space (at least 20-30 GB), because of course, Windows has to make it harder than necessary. Not sure why it works, but cleaning temp files rarely hurts.
- Press Windows + R and type
temp, hit Enter. Delete everything inside. - Repeat with
%temp%. - Make sure your C: drive (or the drive you’re installing to) has free space.
Run Installer from Command Prompt or PowerShell
If the installer still just hangs or throws DLL errors, try launching it with admin rights via command line. Sometimes Windows blocks certain actions unless run through this route. Just open PowerShell or CMD as admin, then navigate to the folder and launch the installer manually.
- Open PowerShell as administrator.
- Type
cd "C:\Path\To\Installer"— replace with your actual folder path. - Run it by typing the filename, e.g.,
setup.exe, and press Enter.
Adjust RAM Usage Settings During Installation
This one’s kinda weird, but if your system has less than 8 GB RAM, some installers bug out if they try to use too much memory. Muting the music option, or limiting RAM usage during setup, can prevent crashes. Why? Because some installers just aren’t optimized for low-memory systems. On certain machines, this alone has made the difference between a failed setup and a successful one.
- If the installer offers options to limit RAM or mute background music, do that.
- Otherwise, close other applications to free up RAM and try again.
Set Game Folder to Exclusions & Re-enable Security
After installing, Windows Security might still block the game or delete files it thinks are threats. To fix that, add your game folder to exclusions:
- Open Windows Security → Virus & threat protection.
- Scroll down and click Add or remove exclusions.
- Click Add an exclusion and pick Folder.
- Navigate to your game folder, e.g.,
C:\Games\YourGameFolder, and select it.
Don’t forget to turn your security back on after. Sometimes, just re-enabling Real-time protection after setup helps avoid weird errors during gameplay or updates.
- Back in Virus & threat protection, turn Real-time protection back on.
Final Prep & Launching the Game
Once installation is pretty much done, check if any additional components like DirectX or Visual C++ redistributables pop up. Installing those can fix a lot of runtime issues later. Also, if there’s a launcher, run it as administrator sometimes prevents weird bugs. Expected result? Once all that is done, you should be able to hit Play and get into the game without errors.
- Install additional components if prompted.
- Set language preferences if needed.
- Launch through the game’s shortcut or executable.
Extra Tips & Common Snags
Some errors are just a sign your system needs a quick check. Make sure your PC meets the game’s minimum specs, especially RAM and storage. Also, keep an eye out for missing files tried to unpack during install—the cause can be corrupt downloads or blocked files. The community around FitGirl is pretty active, so if you hit a weird error, other folks probably found a workaround too.
Wrap-up
Following these steps has helped quite a few users bypass some of the nastiest install errors. Not always foolproof, but if you’re running into setup crashes or DLL issues, it’s worth trying these methods. Sometimes, a simple restart after changing settings can fix surprise conflicts. Ultimately, these fixes aim to get the game installed and ready to play without all the head-scratching glitches.
Frequently Asked Questions
What if the installation still fails after trying all this?
Recheck that you’ve temporarily disabled Windows Security properly, run setup as administrator, and extracted files from a legitimate source. Sometimes, repeated failures hint at corrupted download files or deeper system issues.
Can I just disable Windows Security permanently?
It’s not advised—only disable temporarily during installation. Once done, re-enable it right after. Keeping your system protected is usually more important than a game install.
Is it safe to disable security features?
Only if you trust the source of the installer and remember to re-enable protections afterward. That said, the less you disable security, the better. Just enough to get past the install hurdles.