Problem:
Error dialog appears, "Errors were encountered loading footprints
IO_ERROR: http GET command failed
Cannot get/download Zip archive:
…
Reason: ‘Not found’
…
"
Fix:
Kicad library maintainers removed some deprecated libraries from github between release of RC2 and 4.0.0-stable.
You need to remove the following github libraries from your fp-lib-table:
Capacitors_Elko_ThroughHole.pretty
Housings_SOT.pretty
Housings_SOT-23_SOT-143_TSOT-6.pretty
Housings_SOT-89.pretty
Housings_TO-12_TO-18_TO-42_TO-43.pretty
Housings_TO-50.pretty
Housings_TO-78.pretty
Housings_TO-92.pretty
Transistors_SMD.pretty
Transistors_TO-220.pretty
Transistors_TO-247.pretty
Power_Packages_SMD.pretty
Power_Packages_ThroughHole.pretty
Pentawatts.pretty
Housings_ROHM.pretty
Sockets_PGA.pretty
Sockets_DIP.pretty
Muonde.pretty
Printtrafo_CHK.pretty
Crystals_Oscillators_SMD.pretty
Oscillator-Modules.pretty