Typically, these issues are related to the maintenance of the operating system as a whole, not just only anti-virus. First of all try clean your system drive (usually c:) with stadard Windows clean utility: My computer → c:\ → Properties → Disk Cleanup Include “Service Pack Backup Files”, “Windows Update Cleanup”, “Previous windows installation(s)”, “Temporary windows installation files” as shown in the next picture: Clean up and restart operation system. Note that restart can be too long, not as usual, up to 40..80 minutes, depending on yours hardware. Sometimes it can free tens of gigabytes, and significantly speed up the operating system. Frees the operating system from unnecessary work tracking versions of legacy updates. Sometimes normalizes work of Windows Update service. With antivirus or without it.