| 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.
Run echo %TEMP% in Command Prompt. Try to create a test file: echo test > %TEMP%\test.txt . If access denied, the temp folder is the issue. filezilla not installing on windows 11
Run the installer manually as Administrator: right-click → Run as administrator . If it works, UAC was the blocker. | Symptom | Frequency | |---------|-----------| | Installer