How to Fix FitGirl Setup ISDone.dll & Unarc.dll Error | Game Stuck at Random %

If you are facing the FitGirl Setup ISDone.dll or Unarc.dll error while installing a game and your installation gets stuck at a random percentage, don’t worry. This is a very common problem during game installation, especially with large compressed files.

In this guide, I will show you step-by-step methods to fix ISDone.dll and Unarc.dll errors safely and properly.

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What is ISDone.dll & Unarc.dll Error?

ISDone.dll and Unarc.dll errors usually appear when:

•  Game installation files are corrupted

•  RAM is insufficient

•  Virtual memory is low

•  Antivirus blocks setup files

•  Hard disk has bad sectors

•  Required Visual C++ packages are missing

These errors may show messages like:

•  ISDone.dll error

•  Unarc.dll returned error code -1

•  Installation stopped at random %

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Method 1: Restart PC and Run Setup as Administrator

Sometimes the issue is temporary.

1. Restart your computer
2. Right-click on setup file
3. Click Run as Administrator

Try installing again.

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Method 2: Disable Antivirus Temporarily

Antivirus can block setup extraction files.

1. Turn off real-time protection temporarily
2. Add setup folder to exclusions
3. Run installation again

⚠ Turn antivirus back on after installation.

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Method 3: Increase Virtual Memory (Very Important)

Low virtual memory causes this error.

1. Open Start Menu
2. Search Advanced system settings

3.**** Click Performance → Settings

4. Go to Advanced tab
5. Click Virtual Memory → Change
6. Uncheck “Automatically manage”
7. Set Custom Size:

Initial size: 4096
Maximum size: 8192 (or higher if RAM is low)

Click OK and restart PC.

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Method 4: Install Required Visual C++ Packages

Missing Microsoft Visual C++ redistributables can cause DLL errors.

• Download link is given below

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Method 5: Replace Missing DLL Files

If DLL files are missing or corrupted, download them and place them in:

C:\Windows\System32
C:\Windows\SysWOW64

Download ISDone.dll & Unarc.dll 

• Download link is given below

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Method 6: Check Disk for Errors

Hard drive errors can also cause installation failure.

Open Command Prompt as Administrator and run:

chkdsk C: /f /r

Press Y and restart your computer.

This will scan and fix disk errors automatically.

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Important Notes

•  Make sure you have enough free storage space
• Close background apps during installation
•  Do not install games on corrupted drives
• Always install software from trusted and legal sources

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Final Words

The ISDone.dll and Unarc.dll errors are usually caused by memory issues, corrupted files, or missing system components. By following the methods above, you should be able to fix the problem and complete your game installation successfully.

If this guide helped you, check out our other gaming error fixes on the website.

For a complete step-by-step visual guide, watch the full video here: