Error

[rich2005]

Where did you get the Windows resynthesizer plugin ? Probably an old version that does not work

Get the one from here:

https://www.gimp-forum.net/Thread-Resynt...7#pid12687

Unzip, replace the existing, wherever you installed them. which should be C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins
Four files
plugin-heal-selection.py
plugin-heal-transparency.py
resynthesizer.exe
resynthesizer-gui.exe