Windows Security & Antivirus
Estimated Lesson Time: 20–30 Minutes
Lesson Overview
Welcome to Lesson 7 of Module 2.
In the previous lesson, we looked at background applications and how they can affect Microsoft Flight Simulator performance.
Now we’re going to discuss another topic that is often misunderstood…
Windows Security and Antivirus.
Many optimisation videos tell people to completely disable Windows Defender and antivirus software to gain FPS.
This is one of the biggest myths in PC optimisation.
A fast PC is useless if it becomes infected with malware.
Our goal isn’t simply to gain performance.
Our goal is to build a PC that is:
- Fast
- Stable
- Secure
- Reliable
Throughout this lesson, you’ll learn how Microsoft Defender works, how antivirus software interacts with Microsoft Flight Simulator, when folder exclusions are appropriate, and how to protect your PC without sacrificing security.
Lesson Objectives
By the end of this lesson you will understand:
What Microsoft Defender is.
How antivirus software works.
Why security scans can affect performance.
When Flight Simulator folder exclusions may be appropriate.
What Real-Time Protection does.
What Ransomware Protection is.
How to optimise security while keeping your PC protected.
1. What Is Microsoft Defender?
Microsoft Defender is the built-in antivirus solution included with Windows.
Its job is to protect your computer from:
- Viruses
- Malware
- Spyware
- Trojan horses
- Ransomware
- Suspicious software
- Dangerous downloads
Unlike older versions of Windows, modern Microsoft Defender provides strong protection for most users without requiring third-party antivirus software.
Why Defender Matters
Every day your PC downloads:
Add-ons
Liveries
Aircraft
Scenery
Utilities
Driver updates
Charts
Plugins
Most are completely safe.
Some are not.
Defender helps detect malicious files before they can damage your PC.
Think Of Defender Like Airport Security
Imagine Heathrow Airport.
Every passenger passes through security.
Security checks:
Bags
Passengers
Liquids
Luggage
The process takes a little time…
But it protects everyone.
Microsoft Defender works exactly the same way.
Every file entering your computer is checked.
This creates a small amount of background activity…
But it keeps your system safe.
2. How Antivirus Software Works
Antivirus software constantly monitors your computer.
It checks:
Downloads
Programs
Scripts
Applications
Running processes
Memory
USB devices
Internet activity
Files being opened
Files being modified
If it detects something suspicious…
It can:
Warn you.
Block the file.
Quarantine the file.
Remove the file.
This protection happens automatically.
3. Why Antivirus Can Affect Performance
During normal use…
The performance impact is usually very small.
However…
Microsoft Flight Simulator accesses thousands of files.
Examples include:
Aircraft models
Textures
Scenery
Navigation databases
Community Folder add-ons
Weather files
Every time a file is accessed…
Your antivirus may inspect it.
Normally this happens very quickly.
But on slower systems or systems with very large Community folders…
It can contribute to longer loading times or increased disk activity.
Does Antivirus Reduce FPS?
Usually…
No.
The larger impact is typically on:
Loading times.
Installation speed.
Add-on loading.
Disk activity.
Background CPU usage during scans.
It is uncommon for antivirus alone to reduce FPS significantly during normal gameplay.
4. Security Scans
Microsoft Defender performs different types of scans.
Examples include:
Quick Scan
Full Scan
Offline Scan
Scheduled Scan
Quick Scan
A Quick Scan checks the most common locations where malware is found.
It usually completes within a few minutes.
Recommended:
Run periodically.
Especially after downloading new software from unfamiliar sources.
Full Scan
A Full Scan checks your entire computer.
Every drive.
Every folder.
Every file.
Because this process is intensive…
It may temporarily use:
CPU
Disk
RAM
Network
Do not begin a long Flight Simulator session while a Full Scan is running.
Offline Scan
Offline Scans restart the computer before Windows loads.
This allows Defender to remove malware that may otherwise be difficult to detect.
Most users will rarely need this feature.
Scheduled Scans
Microsoft Defender automatically performs scheduled scans.
If one begins while you’re flying…
It may increase CPU or disk activity.
If you notice unusual performance, check Windows Security to see whether a scan is currently in progress.
5. Flight Simulator Folder Exclusions
An exclusion tells Microsoft Defender not to scan a specific trusted folder.
This can reduce unnecessary file scanning.
For Flight Simulator users, possible exclusions may include:
The Microsoft Flight Simulator installation folder.
The Community folder.
The Official folder.
Why Use Exclusions?
MSFS loads thousands of files.
If Defender scans every file every time it is accessed…
Loading may take slightly longer.
Adding exclusions for trusted MSFS folders can reduce repeated scanning of known-safe files.
Important Safety Warning
Only add exclusions for folders that you trust.
Never exclude:
Downloads
Desktop
Entire drives
Unknown software folders
Adding unnecessary exclusions reduces your security.
Use them carefully.
How To Add An Exclusion
Open:
Windows Security
↓
Virus & Threat Protection
↓
Manage Settings
↓
Exclusions
↓
Add or Remove Exclusions
↓
Select:
Folder
↓
Choose your trusted MSFS folder.
Remember: Only do this if you understand the folder contents and trust them.
6. Real-Time Protection
Real-Time Protection is one of Defender’s most important features.
It continuously monitors:
New files.
Running programs.
Downloads.
System changes.
USB devices.
Without Real-Time Protection…
Malware could run before Defender has a chance to detect it.
Should You Disable Real-Time Protection?
For almost everyone…
No.
Some online guides suggest disabling it permanently.
This is poor security advice.
The performance benefit is usually small, while the security risk is significant.
If you need to troubleshoot a very specific issue, temporarily disabling it may help identify whether Defender is involved—but remember to re-enable it immediately afterwards.
For day-to-day use, keep Real-Time Protection enabled.
7. Ransomware Protection
One of the biggest cybersecurity threats today is ransomware.
Ransomware attempts to:
Encrypt your files.
Lock your documents.
Demand payment.
Prevent access to your data.
Windows includes Controlled Folder Access to help protect important folders from unauthorised changes.
How It Works
Controlled Folder Access monitors protected folders.
If an unknown application tries to modify those folders…
Windows blocks it.
Examples include:
Documents.
Pictures.
Desktop.
Other protected folders.
Why It Matters
Many simmers spend hundreds of hours building:
Community folders.
Flight plans.
Profiles.
Controller configurations.
Graphics settings.
Backing up and protecting this work is important.
Should You Enable Ransomware Protection?
For most users:
Yes, if you’re comfortable managing the prompts it may generate.
However, some legitimate applications may need to be allowed through Controlled Folder Access if they require access to protected folders.
If you enable this feature and a trusted application is blocked, review the prompt carefully before allowing it.
8. Third-Party Antivirus Software
Some users install antivirus programs such as:
Bitdefender
ESET
Norton
McAfee
Kaspersky (availability varies by region)
Many work well.
However…
Some third-party antivirus suites include additional background services that can consume more resources than Microsoft Defender.
If you are already using Microsoft Defender and it meets your needs, there is often no requirement to install a second antivirus solution.
Running two real-time antivirus programs simultaneously is generally not recommended, as they can conflict and increase resource usage.
9. Best Practices For Flight Simulator Users
Before flying:
Check whether a Full Scan is running.
Pause it if appropriate and resume it afterwards.
Keep Microsoft Defender updated.
Keep Real-Time Protection enabled.
Use exclusions only for trusted MSFS folders.
Avoid downloading aircraft or scenery from unknown websites.
Back up important files regularly.
Maintain good security habits alongside good optimisation habits.
Student Exercise
Today we’re going to review your Windows Security settings.
Step 1
Open:
Windows Security.
Step 2
Select:
Virus & Threat Protection.
Step 3
Confirm:
Real-Time Protection is enabled.
Step 4
Check:
Protection Updates.
Ensure Microsoft Defender has the latest security definitions.
Step 5
Review:
Exclusions.
If you use exclusions, confirm they only include trusted Microsoft Flight Simulator folders.
Remove any unnecessary or unknown exclusions.
Step 6
Review:
Ransomware Protection (Controlled Folder Access).
Understand how it works and whether it is appropriate for your setup.
Step 7
Verify:
No Full Scan is running before beginning a long MSFS session.
Student Checklist
Microsoft Defender reviewed.
Security definitions updated.
Real-Time Protection enabled.
Exclusions reviewed.
Only trusted folders excluded.
Ransomware Protection understood.
No unnecessary antivirus software running.
Full scan not running before launching MSFS.
Lesson Summary
Congratulations.
You now understand how Windows Security and antivirus software fit into a well-optimised Flight Simulator PC.
Remember:
- Microsoft Defender provides strong built-in protection for most users.
- Antivirus software helps protect your system by scanning files and monitoring activity.
- Security scans can temporarily increase CPU, RAM, Disk, or Network usage.
- Exclusions may improve loading efficiency for trusted Flight Simulator folders but should be used carefully.
- Real-Time Protection should generally remain enabled.
- Ransomware Protection helps protect important files from malicious software.
- Security and performance should work together—optimisation should never come at the cost of leaving your PC unprotected.
Knowledge Check
- What is Microsoft Defender?
- Why can antivirus software sometimes affect loading times?
- Should Real-Time Protection normally be left enabled? Why?
- What is the purpose of folder exclusions?
- Why should exclusions only be added to trusted folders?
- What does Ransomware Protection help defend against?
- Why is it generally a bad idea to disable all antivirus protection just to try to gain a small performance improvement?