Error "Installation files are not signed”
When installing a Kaspersky application, you may receive the error message “Installation files are not signed”.
This error might be caused by a malicious program that adds certificates of the protection solutions to the Untrusted Certificates folder. This prevents anti-virus programs from installing and launching.
Follow the steps below to solve the issue.
Step 1. Check the system date on your computer
Check the system date on your computer. For instructions, see this article. If the system date is wrong, correct it and try to activate the Kaspersky application once again.
Step 2. Check the digital signature of the installer
- Make sure that the digital signature of the Kaspersky application installer is genuine.
- If the digital signature is invalid or damaged, download the application installer.
- Try installing the Kaspersky application once again.
Step 3. Check for the latest Windows updates
Make sure that the latest Windows updates are installed on your device. See the instructions for all versions on the Microsoft website.
Step 4. Check if required root certificates are installed (applicable to Windows 7 and Windows 8)
For successful verification of the installation file signature in Windows 7 and Windows 8, install the DigiCert Trusted Root G4 root certificate:
- Open DigiCert.
- Find the DigiCert Trusted Root G4 certificate in the table and click Download DER/CRT.
- Open the downloaded file and click Install certificate.
- Click Next.
- Select Place all certificates in the following store and click Browse.
- Select Trusted root certification authorities and click OK.
- Click Next → Finish.
Root certificate will be installed. After successful installation, try installing a Kaspersky application once again.
Step 5. Update Windows root certificates
Step 6. Remove malware from your computer
For Windows XP and Vista, use the previous version of Kaspersky Virus Removal Tool.
Step 7. Check if there are any Kaspersky certificates in the Untrusted Certificates folder
Administrator privileges are required for viewing certificates in the repository of the local computer.
- Press +R on the keyboard to open the Run command box.
- In the Run command box (Launch program in Windows XP), type mmc.
- Click ОК.
- From the File menu, choose Add/Remove Snap-in.
- In the Add/Remove Snap-in dialog box, select Certificates and click Add.
- In the Certificates snap-in window, select Computer account and click Next.
- In the Select Computer dialog box, click Finish.
- Click ОК.
- In the Console Root window, expand the directory Certificates (local computer) and select Untrusted Certificates.
- If you see any protection software certificates in this folder or one of its subfolders, delete the certificates and then retry installing the Kaspersky application.
Step 8. Contact Technical Support
If the issue persists, submit a request to Kaspersky technical support by choosing the topic of your request.
Technical support for Kaspersky Free is not provided. You can ask a question about your issue on our Forum or look it up in the existing topics.
If you want full technical support, buy and install a supported Kaspersky application for home.