Trouble with addonCollectionManager

[rich2005]

Quote: default folders, appended to \Users. But I avoid them like the plague....

I suspected someting like that. (your are talking to the (linux) converted where I have much installed and running from a storage partition).
AFAIK unless you use a portable Gimp you will get a C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\ set of files and folders. What does Edit -> Preferences -> Folders show Did you maybe delete the default path(s)

The plugin just copies then deletes to that location.

With Gimp 2.10.22 installed on a Drive F: I can get it working with (just the beginning of the ini file) and the files stored in sub-folders (xxx_resource) under a main folder F:\resource\

Code:

#-------------------------------------------------------------------------
[all]
# enable:brushes dynamics fonts gradients palettes patterns scripts
enable:brushes fonts patterns scripts
addons_active:{GimpUser}/{type}
addons_stored:F:/resource/{type}_storage
menu_location:{<type>}
menu_entry:{type} sets...
menu_description:Manage {type} sets...
dialog_title:{type} sets manager
[brushes]
menu_location:<Image>/Resource
extensions:.gbr  .vbr  .gih  .abr  .GBR  .VBR  .GIH

Ofnuts might have some solution, possibly starting Gimp from a batch file where new Gimp environmental variables are set.