Microsoft Defender threat service stopped
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Phase 2 Error Library
Security and Malware Alerts
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence. Browse 50 individual troubleshooting guides with safe repair steps and support options.
Category overview
50 detailed guides
Safe, reversible troubleshooting
Related guides and support
Microsoft Defender definitions will not update
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Microsoft Defender error 0x800106ba
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Microsoft Defender error 0x800704ec
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Microsoft Defender controlled folder access blocked app
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Windows Firewall will not turn on
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Windows Firewall error 0x80070422
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Windows Security app will not open
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Windows Security shows actions recommended
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Tamper Protection cannot be enabled
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Ransomware note appeared
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Browser redirects to unwanted sites
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Fake virus warning pop-ups
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Computer is infected with adware
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Unknown remote access software found
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Suspicious startup program detected
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Antivirus quarantined a required file
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Malware scan keeps stopping
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Threat returns after removal
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Potentially unwanted application detected
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Credential theft alert on computer
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Impossible travel sign-in alert
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Microsoft account unusual sign-in activity
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Email account sending spam
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Outlook inbox rule was created unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Browser password breach alert
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Windows account locked after failed sign-ins
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →BitLocker was enabled unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Files were encrypted and renamed
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Remote Desktop brute-force attempts detected
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Cryptomining process using high CPU
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Unknown scheduled task keeps returning
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Unknown Windows service installed
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Hosts file was modified
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →DNS settings changed unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Proxy settings changed by malware
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Chrome managed by your organization unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Edge managed by your organization unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Antivirus subscription scam pop-up
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Tech support scam phone number pop-up
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Webcam or microphone access alert
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →USB malware infection suspected
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Macro malware blocked in Office
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →PowerShell malware alert
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Living-off-the-land binary alert
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Suspicious WMI persistence detected
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Suspicious account added to administrators
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Firewall rule created unexpectedly
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Security log was cleared
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
View resolution guide →Computer compromised after phishing email
Microsoft Defender, firewall, ransomware, browser hijacking, account compromise, and suspicious persistence.
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