Step-by-step fix guide for installs that freeze, hang or stall at 99% on Windows 10 and Windows 11.
A slow step is not the same as a frozen one. The installer can pause while it registers the MBAMService background service, especially at the end. Wait about two minutes before assuming it is truly stuck.
Press Ctrl+Shift+Esc to open Task Manager. Under the Details tab, end any process named MBSetup, mbam, MBAMService or Malwarebytes. This releases the lock that is freezing the installer.
A third-party antivirus can hold the installer mid-write. Open it and pause real-time protection for 10 minutes, or temporarily disable it, then retry the install.
The installer needs at least 2 GB free. Open Settings → System → Storage and clear temporary files if you are low, then try again.
Restart Windows so no leftover processes are running. Immediately after login, right-click MBSetup.exe → Run as administrator and install before other startup apps load. Use a freshly downloaded installer in case the previous file was corrupted.
If it still stalls, download the free Malwarebytes Support Tool, choose Clean to remove every half-installed component, reboot, then install a fresh copy from malwarebytes.com.
A stuck Malwarebytes install is usually caused by a background process holding a lock — often a previous Malwarebytes service, an active third-party antivirus, or a corrupted MBSetup download. Insufficient disk space and a pending Windows restart can also freeze the installer.
Yes. If the installer has been frozen for several minutes, ending it in Task Manager will not harm Windows. After force-closing, end any leftover Malwarebytes processes, reboot, and run a fresh installer as Administrator.
A freeze at 99% usually means the installer is waiting on the MBAMService registration. Wait two minutes, then if nothing changes, end the process, reboot Windows, and reinstall. Running the Malwarebytes Support Tool first clears any half-registered service.