| Symptom | Frequency | |---------|-----------| | Installer launches, then disappears without error | High (~40%) | | "Windows protected your PC" (SmartScreen) | High (~30%) | | "Installation directory is not writable" | Medium (~15%) | | Missing MSVCP140.dll or VCRUNTIME140.dll error | Medium (~10%) | | Installation hangs at "Registering services" or "Installing shell extension" | Low (~5%) | | Error 5 (Access Denied) when writing to Program Files | Low (~5%) | Cause 1: User Account Control (UAC) Blocking Elevation Technical Explanation: FileZilla installer requires write access to C:\Program Files\FileZilla FTP Client and registry keys under HKLM\SOFTWARE . Without administrative elevation, the installer cannot copy files or register protocol handlers (ftp://). Windows 11 may silently fail elevation if the executable is unsigned or untrusted.
Check Windows Security → Device security → Core isolation details . If Memory Integrity is On , try turning it off temporarily. filezilla not installing on windows 11
Always right-click the installer and select Run as administrator . If the issue persists, temporarily lower UAC to "Notify me only when apps try to make changes" (not recommended permanently). Cause 2: Windows SmartScreen / Defender Blocking Technical Explanation: FileZilla installer is code-signed but not always with an EV (Extended Validation) certificate. SmartScreen may flag it as "unrecognized," especially if downloaded via HTTP (not HTTPS) or from a mirror. | Symptom | Frequency | |---------|-----------| | Installer
Check if SmartScreen shows a blue or yellow screen saying "Windows protected your PC." Click More info → Run anyway . Check Windows Security → Device security → Core