I want to switch antivirus products — how do I do it correctly?

Switching antivirus products has a specific failure mode: installing the new product on top of the old one. Running two real-time AV engines simultaneously causes conflicts — doubled file system hooks, competing access to the same files, and sometimes each product flagging the other's temporary scan artifacts. The new product may also install incompletely if the old product's kernel drivers are still active.

Quick answer

Ready to switch — what's the correct order?→Uninstall current AV completely using the vendor's removal tool → reboot → install new AV → verify Windows Security shows the new product as active

Want a cleanup scan before switching→Run Malwarebytes Free first — on-demand, no installation conflict, clears any existing infection before the new product takes over

Switching because the current product is too slow→ESET is the lowest-overhead full-featured replacement; uninstall the current product cleanly before installing

When it matters

Order matters. Skipping steps creates conflicts that are more disruptive than the switch itself:

Download the new AV installer before starting the uninstall — this avoids a window where you're downloading software with no protection active
Uninstall the current product through Settings → Apps, not just by deleting files — partial uninstalls leave kernel-level drivers that conflict with the new product
Use the old vendor's removal tool if one exists — Bitdefender, Norton, ESET, and others publish dedicated uninstall utilities that remove residual components the standard uninstaller misses; search '[vendor name] removal tool' on the vendor's site
Reboot after uninstall, before installing the new product — this clears loaded kernel modules from memory
Verify in Windows Security after installation — check that the new product is listed as active for real-time protection and that Windows Defender is correctly suspended

When it fails

Residual kernel drivers from the old product can cause the new product to fail to install or install with reduced functionality — the removal tool step is not optional.
Windows Security may show both products as partially active after an incomplete switch — this creates a false sense of coverage while neither product is functioning correctly
Some AV products require a specific uninstall sequence if they include a firewall component — removing just the AV without removing the firewall can leave an orphaned firewall that conflicts with Windows Defender Firewall

The protection gap during the switch is real but brief — typically the time between uninstall and reboot plus the new product installation, measured in minutes on a modern machine. Avoiding risky activity during that window is reasonable; the gap doesn't justify skipping the clean uninstall.

How providers fit

Malwarebytes fits as a pre-switch scan. Run the free on-demand version before uninstalling the old product — it confirms the machine is clean before the transition. No real-time component means no conflict with the old AV during the scan. This is the sequence: scan with Malwarebytes → confirm clean → then begin the uninstall-reinstall switch.

ESET fits as the destination product if performance is the reason for switching. Clean installer, correct Windows Security Center registration, and a dedicated removal tool published by ESET for cleaning up competing products before installation. Lowest measured overhead of full-featured AV products post-installation.

Bitdefender fits as the destination product if detection quality or Autopilot mode is the reason for switching. Publishes a removal tool for competing products. Installs cleanly after a correct uninstall of the old product. Windows Defender handoff is handled automatically on first run.

Bottom line

Scan with Malwarebytes Free first. Then: old vendor's removal tool → reboot → install new product → verify in Windows Security. The sequence is usually completed within a short maintenance window on a modern machine. Skipping the removal tool step is the most common source of post-switch problems.

My subscription is expiring — renew or switch?→Can I run my AV and Windows Security at the same time?→I want strong protection without slowing things down→