If you are an ESET user, you likely value the software for its lightweight design, high detection rates, and low system footprint. However, even the most reliable security suites can occasionally run into technical issues. One of the most persistent and frustrating errors encountered by users of ESET NOD32 Antivirus and ESET Smart Security is the infamous Error Code 803191 .
Open your ESET product (NOD32 Antivirus or Smart Security). Step 2: Press F5 on your keyboard to open the Advanced Setup window. Step 3: In the left-hand tree menu, navigate to: Update → Profiles → Update (Default profile) Step 4: Click on Clear update cache next to the cache information. Step 5: A confirmation dialog will appear. Click Yes . Step 6: Immediately click on Update in the left-hand tree menu again and select "Empty update cache and roll back partial updates" (this option appears after clearing the primary cache). Step 7: Click OK to save changes and close Advanced Setup. Step 8: Return to the main ESET window and manually click Update → Check for updates . eset nod32 antivirus and smart security 803191 fixed
Right-click the system clock in your taskbar and select Adjust date/time . Step 2: Ensure "Set time automatically" and "Set time zone automatically" are toggled ON . Step 3: Click Sync now under "Additional settings". Step 4: If sync fails, manually correct the year, month, and day. Pay special attention to the year (e.g., 2026, not 2025 or 2027). Step 5: Close the settings, restart your PC, and then attempt to update ESET again. Method 3: Check for Firewall or Third-Party Antivirus Conflicts If you have another security product installed (even a disabled one), or if Windows Defender Firewall is blocking ESET, you will see 803191. If you are an ESET user, you likely