Avantguard Computer & Security Systems

Add Unsigned Certificate

Install a Self-Signed or Untrusted Certificate

Method 1: MMC (Microsoft Management Console)

  1. Press Win+R, type mmc, press Enter
  2. File > Add/Remove Snap-in
  3. Select Certificates, click Add
  4. Choose Computer account > Local computer
  5. Expand Certificates (Local Computer)
  6. Right-click Trusted Root Certification Authorities > All Tasks > Import
  7. Follow the wizard to import the .cer or .crt file

Method 2: Command Line

# Install to Trusted Root CA store (machine-wide)
certutil -addstore -f "ROOT" certificate.cer

# Verify installation
certutil -store ROOT | findstr "YourCertName"

# Install to Personal store
certutil -addstore -f "MY" certificate.cer

Method 3: PowerShell

# Import to Trusted Root CA
Import-Certificate -FilePath "C:\path\to\cert.cer" `
    -CertStoreLocation Cert:\LocalMachine\Root

# Import to Personal store
Import-Certificate -FilePath "C:\path\to\cert.cer" `
    -CertStoreLocation Cert:\CurrentUser\My

Clear IE/Edge SSL State

After adding the certificate, clear the SSL state:

  1. Internet Options > Content tab
  2. Click Clear SSL state
  3. Restart browser

Or via command line:

certutil -URLCache * delete

For Java Applications

keytool -importcert -alias "mycert" \
    -file certificate.cer \
    -keystore "%JAVA_HOME%\lib\security\cacerts" \
    -storepass changeit