ByIntroduction
Today, Windows Security (formerly Windows Defender) is the most important security layer for every Windows user. However, users are sometimes troubled by the problem that Windows Security repeatedly detects the same virus or threat every time the PC starts, even if it has already been removed or quarantined. This situation not only creates confusion but also raises questions about the system’s reliability.
Here, we present a complete, practical, and permanent solution to this problem so that your system remains secure, stable, and warning-free.
Why Windows Security Shows the Same Virus on Startup
There can be several technical reasons behind this problem, the main ones being:
The threat is not being completely removed
Malware remaining in Startup Programs or Scheduled Tasks
Corruption in Cache or Detection History
False Positive Detection
Malware present in System Restore Points
Third-Party Software Conflict
By understanding these reasons, we can eliminate the problem from its root.
Step 1: Completely Clear Windows Security Protection History
Sometimes the virus has been removed, but its record remains in the Protection History, causing the same alert to reappear on startup.
How to do it
1. Open Windows Security
2. Go to Virus & Threat Protection
3. Open Protection History
4. Select each old threat and Remove / Allow / Dismiss it
After this, restart the system and check.
Step 2: Manually Delete Hidden Malware Files
Sometimes malware files remain hidden in the system.
Advanced Method
Open File Explorer
Enable View → Hidden Items
Check these locations:
C:\ProgramData
C:\Users\YourName\AppData\Local
C:\Users\YourName\AppData\Roaming
C:\Windows\Temp
If you see any suspicious files, delete them.
Step 3: Check Startup Programs and Services
Malware often adds itself to the Startup. How to Clean Up Startup Programs
1. Open Task Manager by pressing Ctrl + Shift + Esc
2. Go to the Startup Tab
3. Disable any Unknown or Suspicious Programs
Check Services
Win + R → services.msc
Disable Unknown Services
Step 4: Remove Hidden Viruses in Scheduled Tasks
Many viruses add themselves to the Task Scheduler so they can become active on every startup.
How to Remove
1. Win + R → taskschd.msc
2. Open Task Scheduler Library
3. Delete Unknown or Suspicious Tasks
Step 5: Reset Windows Defender Cache
A corrupted Windows Security cache can cause false alerts.
Clear Cache from Command Prompt
1. Open CMD as Administrator
2. Run these commands:
“`
net stop WinDefend
del /s /q C:\ProgramData\Microsoft\Windows Defender\Scans\History
net start WinDefend
“`
3. Restart the system
Step 6: Perform a Deep Scan with Offline Scan
Online scans sometimes fail to detect hidden threats.
Windows Defender Offline Scan
1. Windows Security → Virus & Threat Protection
2. Scan Options
3. Select Microsoft Defender Offline Scan
4. Click Scan Now
This scan checks the system thoroughly after a restart.
Step 7: Delete System Restore Points
If old restore points contain malware, Windows Security will repeatedly give alerts.
How to Delete
1. Control Panel → System
2. System Protection
3. Configure → Delete All Restore Points
4. Create a new Restore Point
Step 8: Identify False Positive Detections
Sometimes Windows Security mistakenly identifies a safe file as a virus.
Solution
Carefully note the virus name and path
If the file is associated with trusted software:
Select Allow on Device
Or reinstall the software from the official source
Step 9: Update Windows Updates and Security Definitions
Outdated virus definitions can also cause false alerts. How to Update
Settings → Windows Update → Check for Updates
Windows Security → Virus & Threat Protection Updates
Step 10: Resolve Third-Party Antivirus Conflicts
If your system has more than one antivirus program installed, a conflict may occur.
What to do:
Keep only one antivirus program.
Completely uninstall all other security software.
Restart your computer and run a scan again.
Important Tips to Avoid This Problem in the Future
Download software only from trusted websites.
Avoid cracked or pirated software.
Do not open USB drives without scanning them.
Run a full scan regularly.
Keep Windows and drivers updated at all times.
Conclusion
If Windows Security is repeatedly showing the same virus on startup, this problem may seem serious, but by following the correct procedure, it can be completely and permanently resolved. By implementing all the steps above in order, your system will not only be secure but also free from unnecessary alerts.
Our goal is to provide you with a solution that is practical, effective, and long-lasting.
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Frequently Asked Questions (FAQ)
Question 1: Why does Windows Security repeatedly show the same virus on startup?
Answer: The main reason is that the virus or malware has not been completely removed. Sometimes a file remains in the Startup programs, Scheduled Tasks, Cache, or System Restore points, causing Windows Security to detect it again every time.
Question 2: Is this virus actually present in the system, or could it be a false warning?
Answer: Both situations are possible. In some cases, it’s a false positive detection, where Windows Security mistakenly identifies a safe file as a threat. However, in most cases, some part of the malware is still present in the system.
Question 3: Can clearing the Protection History solve the problem?
Answer: Yes, sometimes simply clearing the Protection History stops the virus alert from appearing on startup, especially if the threat has already been removed but the record remains.
Question 4: What is a Windows Defender Offline Scan, and why is it necessary?
Answer: An Offline Scan runs before the system boots, allowing for the easy removal of hidden or active malware. This scan is very effective against viruses that are not detected by a normal scan.
Question 5: Can a third-party antivirus cause this problem?
Answer: Yes. If more than one antivirus is installed on the system, they can conflict with each other, causing Windows Security to repeatedly show false alerts. Always use only one antivirus program.
Question 6: Will deleting System Restore Points affect my data?
Answer: No, deleting System Restore Points does not affect your personal files. It only removes old restore snapshots, which may contain hidden malware.
Question 7: How to identify a virus in Startup Programs?
Answer: Look for programs in the Startup tab with unusual names, unknown publishers, or programs you didn’t install. Disabling such programs is usually safe.
Question 8: Can not updating Windows also cause this problem?
Answer: Yes. If you have an older version of Windows or outdated security definitions, Defender may not be able to handle threats properly and will repeatedly show the same virus. Regular updates are crucial.
Question 9: Is it necessary to reset Windows every time a virus is detected?
Answer: No. In most cases, the methods described above will completely resolve the problem. Resetting Windows should only be a last resort, when no other method works.
Question 10: What is the best way to prevent this problem in the future?
Answer:
Install only trusted software
Avoid pirated or cracked apps
Scan USB and external drives
Run a full system scan regularly
Do not disable Windows Security
