QCAD.org Forum

If you choose to use the free QCAD Community Edition (without the features and tools of QCAD Professional and without DWG support), you can simply remove the trial add-ons from a downloaded and installed QCAD Professional or QCAD/CAM trial version. If you click on "Remove", in the trial widget, QCAD will tell you which files to remove. Depending on your platform, you can find the plugins in:

Windows:
[QCAD installation folder]\plugins

macOS:
QCAD.app/Contents/PlugIns (Right-click on QCAD.app and click Show Package Contents)

Linux:
[QCAD installation directory]/plugins